• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.277-283
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• 2015

MS(Mild Steel), HTS(High Tensile Steel), HYS(High Yield Steel), AL(Aluminum Alloy) and Composite Materials are used for vessels. Steel Materials are mostly used for vessels because body of a ship have to perform the basic functions such as watertight, preserving the strength and supporting the equipments. The vessels primarily carry out a mission at ocean, so that body of a ship is necessarily rusted. There are several methods to protect the corrosion of vessels such as painting, SACP(sacrificial anode cathodic protection) and ICCP(impressed current cathodic protection). For the sacrificial anode cathodic protection, Al and Zn alloys are normally used. Heavy metals are added to the Al and Zn Alloys for improving the corrosion properties but they are so harmful to the human and environment. Therefore, the use of these heavy metals is strictly regulated in the world. In this paper, Al and Zn Alloys are made by adding the trace elements(Ma, Ca, Ce and Sn) which is not harmful to the human and environment. SEM, XRD, Potentiodynamic Polarization test and Current Efficiency test are conducted for evaluation of Al and Zn Alloys. As a result of the experiment, Al-3Zn-0.6Sn and Zn-3Sn Alloys are more efficient than other Alloys.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.60-61
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• 2003

A new approach to reduce the computation time of genetic algorithm (GA) for making binary phase holograms is described. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are proven in computer simulation and experimentally demonstrated. Recently, computer-generated holograms (CGHs) having high diffraction efficiency and flexibility of design have been widely developed in many applications such as optical information processing, optical computing, optical interconnection, etc. Among proposed optimization methods, GA has become popular due to its capability of reaching nearly global. However, there exits a drawback to consider when we use the genetic algorithm. It is the large amount of computation time to construct desired holograms. One of the major reasons that the GA' s operation may be time intensive results from the expense of computing the cost function that must Fourier transform the parameters encoded on the hologram into the fitness value. In trying to remedy this drawback, Artificial Neural Network (ANN) has been put forward, allowing CGHs to be created easily and quickly (1), but the quality of reconstructed images is not high enough to use in applications of high preciseness. For that, we are in attempt to find a new approach of combiningthe good properties and performance of both the GA and ANN to make CGHs of high diffraction efficiency in a short time. The optimization of CGH using the genetic algorithm is merely a process of iteration, including selection, crossover, and mutation operators [2]. It is worth noting that the evaluation of the cost function with the aim of selecting better holograms plays an important role in the implementation of the GA. However, this evaluation process wastes much time for Fourier transforming the encoded parameters on the hologram into the value to be solved. Depending on the speed of computer, this process can even last up to ten minutes. It will be more effective if instead of merely generating random holograms in the initial process, a set of approximately desired holograms is employed. By doing so, the initial population will contain less trial holograms equivalent to the reduction of the computation time of GA's. Accordingly, a hybrid algorithm that utilizes a trained neural network to initiate the GA's procedure is proposed. Consequently, the initial population contains less random holograms and is compensated by approximately desired holograms. Figure 1 is the flowchart of the hybrid algorithm in comparison with the classical GA. The procedure of synthesizing a hologram on computer is divided into two steps. First the simulation of holograms based on ANN method [1] to acquire approximately desired holograms is carried. With a teaching data set of 9 characters obtained from the classical GA, the number of layer is 3, the number of hidden node is 100, learning rate is 0.3, and momentum is 0.5, the artificial neural network trained enables us to attain the approximately desired holograms, which are fairly good agreement with what we suggested in the theory. The second step, effect of several parameters on the operation of the hybrid algorithm is investigated. In principle, the operation of the hybrid algorithm and GA are the same except the modification of the initial step. Hence, the verified results in Ref [2] of the parameters such as the probability of crossover and mutation, the tournament size, and the crossover block size are remained unchanged, beside of the reduced population size. The reconstructed image of 76.4% diffraction efficiency and 5.4% uniformity is achieved when the population size is 30, the iteration number is 2000, the probability of crossover is 0.75, and the probability of mutation is 0.001. A comparison between the hybrid algorithm and GA in term of diffraction efficiency and computation time is also evaluated as shown in Fig. 2. With a 66.7% reduction in computation time and a 2% increase in diffraction efficiency compared to the GA method, the hybrid algorithm demonstrates its efficient performance. In the optical experiment, the phase holograms were displayed on a programmable phase modulator (model XGA). Figures 3 are pictures of diffracted patterns of the letter "0" from the holograms generated using the hybrid algorithm. Diffraction efficiency of 75.8% and uniformity of 5.8% are measured. We see that the simulation and experiment results are fairly good agreement with each other. In this paper, Genetic Algorithm and Neural Network have been successfully combined in designing CGHs. This method gives a significant reduction in computation time compared to the GA method while still allowing holograms of high diffraction efficiency and uniformity to be achieved. This work was supported by No.mOl-2001-000-00324-0 (2002)) from the Korea Science & Engineering Foundation.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.826-832
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• 2007

Unpleasant tastes and odors in drinking water cause same problems for water utilities across Korea. Even though tastes and odors do not create health problems, they are main concerns for consumers who determine the safety of their drinking water. In this study, two different odor producing compounds(geosmin 2-MIB) in the Nakdong river water and rapid sand filtered rater were treated by advanced oxidation of $O_3/H_2O_2$ process. The experimental results showed that the removal efficiency of geosmin with the use of 5 mg/L of $O_3$ and $H_2O_2$ was higher than efficiency with the use of $O_3$ alone for both the raw water and the sand filtered water. And in general, the removal efficiency of geosmin was higher than 2-MIB in the sand filtered water. Under the range of $O_3$ concentration $0.5\sim2.0$ mg/L, the removal rate constants(k) of geosmin for the raw and sand filtered waters, and the one of 2-MIB in the sand filtered water were increased rapidly as doses of $O_3$, and $H_2O_2$, increased. The removal rate constants(k) do not increase any more when $H_2O_2/O_3$ ratio increases above the optimum ratio. The optimum ratio of $H_2O_2/O_3$, dose was $1.0\sim2.0$ for both geosmin and 2-MIB. The removal rate constant(k) becomes lower when OH radical consuming materials are present in raw water. The half-life of geosmin decreased rapidly as the $O_3$ and $H_2O_2$ doses increase in the sand filtered water. The half life decreased about 8.5 times with the use of 2 mg/L of $O_3$ and 10 mg/L of $H_2O_2$ than with the use of 2 mg/L of $O_3$ alone for the sand filtered water.

• Journal of the Korea Society of Computer and Information
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• v.18 no.7
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• pp.165-174
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• 2013

Recently, many universities in Korea have been faced with critical crisis such as the decrease in the number of freshmen, the pressure for tuition cuts, M&A between universities and so on. Nobody has expected that universities will have this kind of difficulties. The universities are making attempts to innovate the quality of education to secure high level of education and to meet social needs to overcome these internal and external environment of crisis. For this innovation, the universities have sought to reduce the budget as well as conducted the self-evaluation to figure out their relative positions annually. Innovations cannot have having the limitation without education funds. Budget spent in universities have influences directly or indirectly on the structural improvement of the finance and on the growth of universities. The purpose of this study is to explore the decision-making method to find the optimal budget allocation so as to minimize the execution budget and to maximize the management evaluation by taking the advantage to analyse the relationship between the evaluation and the budget. Therefore, in this paper, we implement the development of the mathematical model for the University Evaluation and Budget Allocation Optimization in the form of the linear programming.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1172-1178
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• 2011

The purpose of this study was to investigate the status of a school foodservice menu evaluation and the perception of the school's dietitian on menu evaluation. Questionnaires were distributed to 448 school dietitians with an official letter, and a total of 292 responses were used for analysis. More than 90% of the respondents stated that a menu evaluation for the school foodservice was necessary. The major barriers to menu evaluation were "excessive workload" and a "lack of know-how", and the expected benefits were "increased satisfaction of customers" and "increased foodservice efficiency". The menu evaluation for "student preferences", "health improvement", and "ease of quality management" categories were performed in more than 45% of schools. The proportion of subjects who answered that "customer satisfaction" and "increased efficiency of foodservice" were expected benefits of menu evaluation were significantly higher in the menu evaluation group (p<0.05).

• Quality Improvement in Health Care
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• v.1 no.1
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• pp.96-108
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• 1994

Background: An appropriate use of hospital beds can improve productivity of hospital significantly. The authors' previous study revealed that approximately one third of Korean hospital bed days and one sixth of admissions were inappropriately used, when it was measured by Appropriateness Evaluation Protocol(AEP) and Delay Tool modified into Korean situation by the authors. This study aims to evaluate applicability of the instruments in a new hospital. More specifically the study aims to measure appropriateness of the instruments used by newly trained nurse reviewers at a new hospital setting. Methods: In order to evaluate applicability of these instruments, agreement rates of the scores recorded by newly trained nurse reviewers with by skilled nurse reviewer and also compared with the scores recorded by physician's implicit decision were assessed. Agreement rates were derived from concurrent application of AEP and Delay Tool to 52 admissions and 104 patient days from internal medicine, pediatrics, and general surgery of one university hospital. Overall agreement rate, specific nonacute agreement rate, and kappa statistics were used to indicate level of agreement. Results: Overall agreement rates on appropriateness between newly trained nurse reviewers and skilled nurse reviewer were 100% in admission and 98% in bed days. Overall agreement rates on reason for inappropriateness between newly trained nurse reviewers and skilled nurse reviewer were 96% in admission and 91% in bed days. Overall agreement rates between newly trained nurse reviewers and physician reviewer were 86% in admission and 87% in bed days. Conclusion: Results indicated that AEP and Delay Tool were applicable to a new hospital in detecting inappropriate utilization of beds and reasoning of the inappropriateness. These instruments could contribute to enhance efficiency of hospital use, through continuous monitoring of level of inappropriate hospital use at national or individual hospital level.

• The Korean Journal of Emergency Medical Services
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• v.14 no.3
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• pp.71-81
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• 2010

Purpose: To minimize an interruption in chest compression, reduce the hands-off time, the American Heart Association has recommended the ratio of chest compression to ventilation ratio to 30:2 from 2005 CPR guideline to 2010 CPR guideline. However, current studies have shown that the hands-off time was > 10 seconds with that method. For this reason, we devised new CPR method that a ventilation to chest compression ratio of 2:30 to reduce pt assessment time and skipped the assessment step of carotid artery pulse would be a more effective way to reduce the hands-off time & the time to set the CPR. According to the more detailed purpose are listed below. 1) We would like to confirm efficiency of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 to reduce the hands-off time & the time to set the CPR. 2) We would like to evaluate possibility of increasing for chest compression accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 3) We would like to evaluate possibility of increasing for ventilation accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 Methods: According to 2005 American Heart Association Guidelines, 60 paramedic students(20 students X freshmen, sophomore, junior) performed 5 cycles of 3~ chest compressions : 2 ventilations after A, B, C evaluation with Laerdal Resusci R Anne SkillReporters. After 5 minutes rest, the 60 students performed 5 cycles of 2 ventilations : 30 chest compressions after A, B evaluation with the manikins between 13 and 17 September 2010. The short reports including speed & accuracy of chest compression, respiratory, CPR cycle were gained from the manikins. Hands-off times were measured by assistants. Results: Recently, the importance of high quality CPR was emphasized in order to perform the CPR faster and more accurate. To find out improving the conventional CPR method, we switch the procedure of the compression and the ventilation. By switching the procedure back and forth, we are able to compare the effectiveness of CPR between two type of CPR method which are 2:30 and 30:2 methods. 2:30 is that the breaths is delivered twice, first and perform 30 compressions while 30:2 perform 30 compressions first and give 2 breaths followed by the ABC method. Also, we verify the effectiveness of the hands off time, compression accuracy of the compression through the comparison of the two procedure as mentioned earlier. Consequently research verified that 2:30 is the efficient by providing faster set up delivering more accurate chest compression. Conclusion: 2:30 can minimize a time delay from cardiac standstill until starting the chest compression. In addition, hands-off time which is an interruption in chest compression can be shortened by 2:30 method, which result to effective oxygenation of coronary artery & maintenance of the bloodstream. Once again, performing the 2:30 method provide lessen hands off time and increase the accuracy of the chest compression.

• Progress in Medical Physics
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• v.21 no.2
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• pp.223-231
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• 2010

We have taken surveys about total 72 departments of radiation oncology which is performing the treatment with linear accelerator and brachytherapy unit in Korea. The survey was included the research about the linear accelerator, brachytherapy, Also, we surveyed the various performance (QA period, manpower, time) of quality control for understanding of efficiency. The survey results show that the QA test of daily and weekly are almost same comparing to USA and Europe but the QA performance of monthly and yearly in Korea are 15.5 which is less than USA and Europe recommended QA item number of 17 to 21. The manpower and QA time in Korea also lower than 50% of USA and Europe recommended because the manpower and QA time limitation in Korea. It will be expected that the manual of quality management in each clinic could be appropriately established when combining the present results with previously published AAPM TG-40 and other protocols.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.83-85
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• 2001

This experiment was conducted to investigate the effects of pelleted food waste on performance and meat quality of broiler ducks. One hundred-forty four broiler ducks were divided into 4 groups with 3 replicates per treatment for 5 weeks. Dietary levels of food waste 0%, 25%, 50% and 75% were included in experimental diets Daily weight gain was significantly increased by addition of food waste 25% and .50%, whereas decreased(P<0.05) by addition of 75% food waste. Feed intake were not affected by the pelleted food waste supplementations. Feed efficiency was improved(P<0.05) by the addition 25% food waste, however, there was depressed(P<0.05) by the addition of 75% food waste. Carcass weight was significantly decreased(P<0.05) by the addition 75% food waste. Moisture composition of breast meat were not significantly different by 25% and 50% food waste, however, there was significantly increased by 75% food waste. As the food waste level was increased, lipid and protein composition in beast meat was significantly decreased As the food waste level was increased. pH of beast meat was increased, whereas lightness and redness of meat color were decreased. Cholesterol content was significantly decreased(P<0.05) by addition of food waste. Odor and appearance of sensory evaluation was depressed by addition of food waste, whereas taste of sensory evaluation was improved by addition of food waste. There was no pathological findings from liver, spleen and kidney in slaughtered ducks. The results of this study suggests that pelleted food waste 25% and 50% improved broiler ducks performance and meat quality in broiler ducks.