• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2015년도 춘계 학술대회 논문집
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• pp.105-112
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• 2015

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2008년도 High Temperature Superconductivity Vol.XVIII
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• pp.88-88
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• 2008

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.1229-1230
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• 2005

• 한국안전학회지
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• 제28권1호
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• pp.117-124
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• 2013

Emergency operating procedures(EOPs) of nuclear power plants should be described considering the cognitive capability and limitation of operators and provide appropriate information in the aspect of human factors. Procedures which doesn't consider cognitive characteristics of operators can become causes of human errors. In previous researches, in order to reduce these problems related to the description of EOP, an improvement suggestion for EOP writer's guide has been proposed, which is reflected human factors aspects that should be considered when describing EOPs. The proposed items, however, have a necessity to be validated because it was listed from various documents such as standards and guidelines without any special validation process. For that reason, in this study, a validation process were performed to show that procedures, which are described in compliance with the requirement items proposed in the improved EOP writer's guide, have positive effects in the aspects of human errors and performance comparing with previous procedures. Experiments were performed to compare the performances of two tasks which are described in compliance with each writer's guide of before and after the improvement During each task was performed in experiments, changes of physiological responses such as EEG and ECG were measured to evaluate the cognitive workload and the stress of operators in each task. And also, as the performance, frequencies of errors and cognition speeds of each task were evaluated. In the results of the experiment, the portions of the ${\beta}$ wave decreased in the tasks overall after the improvement. In the case of ECG, change rates of the mean of R-R interval were decreased in the tasks after improvement. In the results of the performance, the cognition and the response time of the tasks after the improvement were predominant with statistical significancies. Error times in the tasks after improvement were decreased or same to the tasks before improvement. Conclusively, it was validated that the procedures were described in compliance with the improved EOP writer's guide had effects on the reduction of human errors and improvement of performance.

• KIEAE Journal
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• 제14권6호
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• pp.65-73
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• 2014

Due to the Climate change and resource shortage by global warming, various problems are rising and getting worse around the world. Many countries are doing the considerable efforts to reduce greenhouse gas emissions. The government of South Korea also plans to decrease greenhouse gas emission, the various pilot projects are underway, which includes obligation of energy efficiency 1st rating and greenhouse gas target management system of public buildings. In particular, luxurious government office buildings and energy-wasting public building have issued and emerged as a social problem. Energy efficiency improvement of the existing public office buildings are becoming an important issue recently. This study is proposed the step-by-step energy improvement model according to the building energy efficiency rate in order to reduce the energy consumption. To attain this end, I set up a base model by analyzing the current architectural conditions of the existing public office buildings and grasped the specific properties of building energy consumption through energy simulations. Furthermore, I suggested phased reduction prototypes for the reduction target of energy consumption by applying the methods of the zero energy building plan. This study is expecting that prototypes would give directions when it comes to planning the implementation policy of phased building plan factors, according the building energy consumption reduction goal in the existing public office buildings which are the subject of building energy target management system.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 제32회 펄프종이기술 국제세미나
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• pp.83-125
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• 2007

Increasing energy costs have caused profitability problems for paper suppliers. Therefore unprofitable lines are being closed down. The actions aiming for improved profits are focused either on cost savings or on increasing the capacity of the remaining machines. The runnability of a paper machine and its total efficiency have a significant effect on energy consumption. Producing one ton of waste paper consumes at least as much energy as producing the same amount of sellable end product. New automation solutions enable significant cost-effective improvements to the total efficiency of a line without large investment projects. The measures focus on minimizing changes, interruptions, interruption recovery times and grade change times. Newest actuators, online quality measurements and wet end analysators create an improvement potential, which can be optimally implemented with the latest machine direction control solutions, based on model predictive control concepts. Equally, drying management is significant to the energy consumption. The newest control strategies optimize the use of various drying actuators for different situations; either by responding to changes as efficiently as possible or by using only the cheapest energy sources in stable situations. An even steam supply, which is vital for paper machines, is achieved with control for the power plant steam network. This makes possible to avoid the delays upon starting the paper machine and assure an even steam supply for the drying section and the actuators. This document describes means which have brought significant energy and raw material savings for paper machines. Metso Automation has provided efficiency improvement packages, which are usually based on optimized control of dry weight and drying in all running conditions. The solutions are based on performance analysis, on which the estimations for improvement potential and the necessary actions are based on. Typically benefits on an annual level have been from hundreds of thousands of euros to over one million euro. For example, variations in dry weight have been decreased more than 50%. The results are presented with a few examples. Additionally, the analysis models, adjustment solutions and the changes in running methods with which the results were achieved, are presented.

• 설비공학논문집
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• 제29권10호
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• pp.515-529
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• 2017

EnergyPlus, which is widely used in various fields, provides Simple Window Model, a window model that can be used practically. However, the results of building load using the model are different from those of the standard model. The main cause of the deviation by Simple Window Model was analyzed to be due to the assumption that all windows were considered as single layer. The purpose of this study is to propose a window model that improves the cause of deviation by Simple Window Model and can be easily calculated from the algebraic relations. The proposed window model solved the heat balance equation algebraically by using seven window characteristic coefficients. The coefficient relationships consisted of the heat transmission coefficient and solar heat gain coefficient as input parameters make practical use and calculation possible. As a result of comparing the deviation between each window model by implementing the dynamic analysis method, the proposed window model showed that the deviation of the total heating/cooling energy consumption was reduced to 1/3 compared to Simple Window Model for one year. Although the maximum energy consumption did not show any significant improvement, the indoor temperature evaluation showed significantly reduced deviation.

• 한국수소및신에너지학회논문집
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• 제31권3호
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• pp.293-301
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• 2020

This paper describes a numerical study on the improvement of performance of the 2 vane pump impellers. The design of these impellers was optimized using a commercial computation fluid dynamics code and design of experiments. Geometric design variables were defined by the impeller blade angle distribution. The objective functions were defined as the total head, total efficiency and solid material size of the impellers. The importance of the geometric design variables was analyzed using 2^k factorial designs. The interaction between the total head, total efficiency and solid material size, according to the impeller blade angle distribution, is discussed by analyzing the 2^k factorial design results.

• 전기학회논문지
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• 제56권5호
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• pp.938-943
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• 2007

In this paper, we show that, in case of piezoelectric micropower generator, just replacing Schottky diodes in the bridge rectifier with ultra-low reverse leakage current diodes improves the mechanical-to-electrical energy conversion efficiency by more than 100%. Experimental and PSPICE simulation results show that, due to the ultra-low leakage current, the charging speed of the circuit employing PAD1 is higher than that of the circuit employing Schottky diodes and the saturation voltage of the circuit employing PAD1 is also higher. This study suggests that , when the internal impedance of source is very large (a few tens of $M{\Omega}$) such that maximum charging current is a few microamperes or less, in order to realize literally the energy scavenging system, ultra-low reverse leakage current diodes should be used for efficient energy conversion. Since low-level vibration is ubiquitous in the environment ranging from human movement to large infrastructures and the mechanical-to-electrical energy conversion efficiency is much more critical for use of these vibrations, we believe that the improvement in the efficiency using ultra-low leakage diodes, as found in this work, will widen greatly the application of piezoelectric micropower generator.

• Structural Engineering and Mechanics
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• 제61권4호
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• pp.483-496
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• 2017

Earthquake excitations may induce important amount of seismic energy into structures. Current design philosophy mainly deals with the plastic deformations of replaceable energy dissipating devices rather than damages accumulated on structural members. Since earthquake damage is substantially concentrated on these devices they could be replaced after severe earthquakes. In this study, the efficiency of steel cushion (SC) on seismic improvement of a vulnerable reinforced concrete (RC) frame is determined by means of several numerical simulations. The cyclic shear behaviors of SCs were determined by performing quasi-static tests. The test results were the main basis of the theoretical model of SCs which were used in the numerical analysis. These analyses were performed on three types of RC frames namely bare frame (BF), full-braced frame (F-BF) and semi-braced frame (S-BF). According to analysis results; implementation of SCs has considerable effects in reducing the storey shear forces and storey drifts. Moreover plastic energy demands of structural elements were reduced which indicates a significant improvement in seismic behavior of the RC frame preventing damage accumulation on structural elements. Full-braced frame having SCs with the thickness of 25 mm has better performance than semi-braced frame interms of energy dissipation. However, global energy dissipation demand of S-BF and F-BF having SCs with the thickness of 18 mm are almost similar.