• IE interfaces
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• v.24 no.2
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• pp.156-163
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• 2011

The radiopharmaceutical synthesis for PET (positron emission tomography) is composed of chemical reactions using automated synthetical equipment. Due to the radioactive material, the automated equipment is being frequently developed to replace human operators who conduct dangerous, repetitive and dexterous operations. As to operation, the manipulating program is commonly coded using the spread sheet while the whole actuators are mapped in every step. The process map (program) is changed according to such parameters as temperature of reactor, keeping time, mixture sequence and amount of reagent. In cases of customizing the automated synthetical equipment or developing the new radiopharmaceuticals, lots of experiments should be conducted and the programming mistake is not allowed as it can lead abnormal control of the equipment to leak the radioactive materials. The exact process map has depended on trial and error manner. Thus, this study developed the methodology to tabulate the synthetical process to convert the process map automatically while the synthetical module formation is represented by a network model. The proposed method is validated using the actual radiopharmaceutical synthetical procedure.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1327-1337
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• 2017

Photovoltaic (PV) systems are influenced by disproportionate impacts on energy production caused by frequent mismatch cases. The occurrence of multiple maximum power points (MPPs) adds complexity to the tracking process in various PV systems. However, current maximum-power point tracking (MPPT) techniques exhibit limited performance. This paper introduces an enhanced simulated annealing (ESA)-based GMPPT technique against multiple MPP issues in P-V curve with different PV system structures. The proposed technique not only distinguishes global and local MPPs but also performs rapid convergence speed and high tracking accuracy of irradiance changing and restart capability detection. Moreover, the proposed global maximum power tracking algorithm can be applied in the central converter of DMPPT and hybrid PV system to meet various application scenarios. Its effectiveness is verified by simulation and test results.

• International Journal of Safety
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• v.9 no.2
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• pp.29-34
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• 2010

When doing maintenance works at the trackside of railway, the method which delivers information on approaching of train to maintenance workers through alarm devices such as the flag or indication light, etc., is being used by locating persons in charge of safety alarm in addition to the maintenance workers at fixed distances in the front and rear of the workplace. Workers maintaining at the trackside may collide with the train since they cannot recognize the approach of train although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. The clash or rear-end collision accidents between many maintenance trains called motor-cars can be occurred since there are cases where the signal systems for safe operation of motor-car such as track circuit etc. are blocked or not operated normally. We developed the new safety equipment for protection of trackside maintenance workers using radio frequency signals and bidirectional detection mechanism. The developed safety equipment must analyze the several operational mechanism for each different operation situations. In this paper the analysis results are represented.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.849-859
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• 2022

Feed-water valves (FWVs) are used to regulate the flow rate of water entering steam generators, which are very important devices in nuclear power plants. Due to the working environment of relatively high pressure and temperature, there is strength failure problem of valve body in some cases. Based on the thermo-fluid-solid coupling model, the valve body stress of the feed-water valve in the opening process is investigated. The flow field characteristics inside the valve and temperature change of the valve body with time are studied. The stress analysis of the valve body is carried out considering mechanical stress and thermal stress comprehensively. The results show that the area with relatively high-velocity area moves gradually from the bottom of the cross section to the top of the cross section with the increase of the opening degree. The whole valve body reaches the same temperature of 250 ℃ at the time of 1894 s. The maximum stress of the valve body meets the design requirements by stress assessment. This work can be referred for the design of FWVs and other similar valves.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.6
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• pp.11-18
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• 2011

Accurate modal identification analysis is required to reasonably perform a seismic qualification of safety-related electric equipment installed in nuclear power plants (NPPs). This study evaluates a variation of the modal properties of an electric equipment cabinet structure in NPPs according to the excitation levels. For the study, an actual electric equipment cabinet was selected as a specimen and was dynamically tested by using a portable exciter in accordance with the level of input vibration energy. Tests were classified into two sets: with-door cases, and without-door cases. Frequency response functions were computed from the signals of the acceleration responses and input motions measured from the vibration tests. A polynomial curve fitting algorithm was used to extract the modal properties from the frequency response functions. This study reviews the variation of the modal properties according to the variation of the excitation levels. The results of the study show that the modal frequencies and the modal dampings of the object specimen varies nonlinearly according to the excitation level of the test motion. Attaching the door increases the modal damping of the cabinet.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.138-146
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• 2024

Purpose: The purpose of this study is to find cases of using information and communication technology and smart mobility technology in snow removal vehicles and equipment for rapid and efficient road snow removal in the event of a snowstorm, and to find ways to utilize them. Method: Cases of domestic and overseas snow removal methods are investigated, and snow removal operation methods incorporating new technologies are presented. Result: Most of the operation of snow removal equipment in Korea uses GPS, CCTV, and road traffic information systems, and in the case of overseas, road weather information systems and road snow removal monitoring systems are used. It is expected that snow removal technology using autonomous snow removal vehicles, which are smart mobility, will be developed in the future. Conclusion: The results of this study can contribute to the policy of using snow removal equipment and snow removal vehicles of local governments and related organizations.

• Journal of environmental and Sanitary engineering
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• v.11 no.3
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• pp.53-61
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• 1996

The subject of this study was to analyse overviews of companies which exceed TLV by industry, hazardous factors, and to estimate the numbers of companies measured in 1993 and the implementation rate of working environment measurement by the act of industrial safety and health The result of this study was as follow. 1. The number of cases which exceed TLV was 5,937 companies. In distribution of excess companies by the scale of workers, small scale cases under the 49 workers were 3,150 companies(53.0%) of total cases, medium scale cases between 50 - 299 workers were 2,248 companies(37.9%), and large scale cases over 300 workers were 539 companies(9.1%). By the industry of excess companies, it was marked high rate in manufacture of fabricared metal products(except machinary and equipment), manufacture of textiles of each 1,048 companies(17.7%), and 1,018 companies(17.1%). By the area of excess companies, it was shown high rate in Kyeongki area marked 1,679 companies(28.3%) and Daegu-Kyeongbuk area were marked 1,417 companies (23.9%). By the hazardous factors of excess companies, noise was recorded high rate in 5,160 companies (86.9%), dust was shown in 1,245 companies(21.0%), organic solvent was marked 130 companies(7.9%). The number of excess factors by the company was 1.2. In this result, the more it was bigger scale companies, the more excess factors were much more and the more it was recorded higher rate in noise organic solvent heavy metals, etc. 2. The measured cases in institutes during 1994 were 1,596 companies, and excess cases were 157 companies(9.8%) among them. By the scale of workers, small scale cases under the 49 workers were 190 companies (17.9%) among 1,064 companies, cases of medium scale cases between 50-299 workers were 127 companies (27.9%) among 463 companies, and large scale cases over 300 workers were 31 companies(44.9%) among 69 companies. In this result industry of the highest rate shown was manufacture of basic metals in 20 companies exceeded among 53 companies (37.7%), and was manufacture of pulp, paper production in 14 companies exceeded among 40 companies(35.0%), and the excess rate were high in bigger scale. 3. Companies estimated by the data of excess cases and excess rate in 1993 were 30,474 implementation rate estimated for measurement of working environment was 34.3% of companies in korean industry. In this result, it was comparatively shown of measurement rate for the working environment in manufacture of pulp, paper product, manufacture of machinary and equipment n.e.c., and of high measurement rate and excess rate in manufacture of electrial machinary and apparatus, and manufacture of basic metals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4D
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• pp.357-366
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• 2012

Construction equipment has applied to depreciation over the years, however, the price index for construction equipment is not properly reflected in existing quantity per unit and the local tax law. Thus, this study shows the analysis of the corporate tax law, the local tax law and business accounting standards, characteristics of the domestic depreciation system and depreciation methods, and the capital recovery factor of construction equipment applying the theory for economic efficiency. It also presents cases of depreciation on the basis of quantity per unit and tax law using straight-line depreciation method and declining balance method. It is proposed that the relations of the application system of permissible period for construction equipment and the existing system be explained and the application system of permissible period for construction equipment be imposed. Furthermore, it proposes the development of depreciation tables of construction equipment monthly expenses based on the domestic price index and applications. In addition of that, it proposes the analysis of pros and cons of the methods suggested and application limits of the study and subsequent improvement plans. This study should reflect more rational and objective reality in quantity per unit and tax law.

• Journal of Korean Society for Quality Management
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• v.49 no.3
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• pp.341-358
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• 2021

Purpose: After product development, a Reliability Demonstration Test(RDT) is performed to confirm that the target life has been achieved. In the RDT, there are cases where the test equipment cannot accommodate all samples. Therefore, this study considers a test method to most economically demonstrate the target life of the product at a certain confidence level when the sample size is larger than the capacity of the test equipment. Methods: If the sample size is larger than the capacity of the test equipment, test equipments may be added or the test time of individual samples may be increased. So the test method is designed to cover this situation with limited capacity. A zero-failure test method is applied as a test method to RDT. To minimize the cost, the test cost is defined and the cost function is obtained. Finally, we obtain the optimal test plan. Results: A zero-failure test method is designed when the sample size is larger than the capacity of the test equipment, and the expected total cost is derived. In addition, the process of calculating the appropriate sample size, test time, and number of test equipment is illustrated through an example, and the effects of model parameters to the optimal solutions are investigated numerically. Conclusion: In this paper, we study a zero-failure RDT with test equipment that has limited capacity. The expected total cost is derived and the optimal sample size, test time, and number of test equipment are determined to minimize the expected total cost. We also studied numerical examples and for further studies, we can relax some restrictions in the test model and optimize the test method.

• Journal of the Korea Institute of Construction Safety
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• v.4 no.1
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• pp.9-15
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• 2021

Recently, buildings have become larger, more complex, and various construction methods have been tried. As a result, the use of construction equipment continues to increase, as well as safety accidents. According to the Ministry of Employment and Labor's report on industrial accidents, the rate of deaths caused by construction equipment among construction accidents has been increasing steadily since 2009. In the safety field of other industries such as crime and traffic, research has been continuously conducted to develop quantitative indicators due to demands for development of evaluation indicators or risk index development. On the other hand, construction equipment has been studied to analyze disaster cases and come up with improvement measures, but there is no research related to risk index. Therefore, the research will develop a quantitative index that can determine the risk level of construction equipment in the field based on the accident case and verify the possibility of use in the field.