• 감성과학
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• 제4권1호
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• pp.23-31
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• 2001

Psychological and physiological effects from simulator sickness could be an important bias factor for sensibility evaluation. The present experiment investigated the effects of simulator sickness on sensibility evaluation in the controlled condition of driving a car for 60 minutes on a constant speed (60km/h) in graphic simulator. The simulator sickness was measured and analysed for every five minutes using their subjective evaluation and physiological signals. Results of the subjective evaluation showed that there was significant difference between rest and driving condition at 10 minutes from the start of driving, and the level of difference was increased linearly with time. The analysis on central and autonomic nervous systems showed the significant difference between rest and driving conditions after 5 minutes from the start of the driving on the parameters $\alpha$/total and $\beta$/total, and increased level of sympathetic nervous system. But there was no significant difference between different time conditions. The results indicates that physiological changes from simulator sickness can be a bias factor in objective evaluation of human sensibility which also, uses physiological signals. That is, the changes on the parameter $\alpha$/total and $\beta$/total, and on activation level of sympathetic nervous system from simulator sickness can be a bias factor for evaluation of the level of pleasantness and tension. Therefore the effort on improving the analysis by minimizing or eliminating the bias factors should be done for better and accurate sensibility evaluation in simulator environments.

• Asian-Australasian Journal of Animal Sciences
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• 제8권1호
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• pp.67-73
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• 1995

This study showed that models of energy utilization(EU) developed for grazing cattle in oil palm plantations is valid as the simulated results shows an agreement with actual data of calves and cows body weight changes collected from Brahman x Kedah-Kelantan herd on Pengeli Timor Plantation. Simulation runs on EU models demonstrated that the growth pattern of male and female calves and the weight changes of cows are similar and showed slight variation from the actual data but with no significant difference (p > 0.05). Parameter values such as metabolizability (q), dry matter digestibility(DMD) of herbage and voluntary intake of grazing cattle (VIG) and faecal output/body weight ratio (F) of the animals which were collected from the field are essential in bearing the pattern of body weight changes of the calves and cows in relation to increase in time, physiological status and quality of herbage grazed by these animals in the production system. The EU models is suitable for determining the metabolizable energy requirements and to predict the production of grazing cattle according to quality of the feed on offer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.389-392
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• 2008

This paper predicts the changes of natural frequencies due to the changes of mass at different point mass stations by using iterative calculation Transfer Matrices Method for different boundary conditions of a single beam structure (fixed-free and fixed-fixed beam). Firstly, the first three natural frequencies of an original beam are obtained using Transfer Matrices Method to verify the accuracy of the obtained results. The results are then compared with the exact solutions before purposely changing the parameter of mass. Both beams are modeled as discrete continuous systems with six-lumped-mass system. A single beam is broken down into a point mass and a massless beam which represent a single station and expressed in matrix form. The assembled matrices are used to determine the value of natural frequencies using numerical interpolation method corresponding to their mode number by manipulating some elements in the assembled matrix.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1144-1151
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• 2012

A damage in structure alters its dynamic characteristics. The change is characterized by changes in the modal parameter, i.e., modal frequencies, modal damping value and mode shape associated with each modal frequency. Changes also occur in some of the structural parameters; namely, the mass, damping, stiffness matrices of the structure. In this paper, evaluation of changes in stiffness matrix of a structure is presented as a method not only for identifying the presence of the damage but also locating the damage. It is shown that changed stiffness matrix can be accurately estimated a sensitivity coefficient matrix derived from modifying mode shapes, First, with 4 story shear structure models, the effect of presence of damage in a structure on its stiffness matrix is studied. By using these analytical model, the effectiveness of using change of stiffness matrix in detecting and locating damages is demonstrated. To validate the predicted changing stiffness and its location, the obtained results are compared to the reanalysis result which shows good agreement.

• 한국수산과학회지
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• 제47권6호
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• pp.860-868
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• 2014

The study was performed to investigate changes in hematological responses and antioxidative enzyme activities (superoxide dismutase, SOD; catalase, CAT) of Japanese eel Anguilla japonica following exposure to 0 (control), 2.33, 4.60, 6,64 and 8.78 mM nitrite-N in fresh water for 48 h. Hematological parameters such as plasma nitrite, electrolytes, cortisol, glucose, glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), hemoglobin (Hb), methemoglobin (metHb) and NADH-methemoglobin reductase (NMR) were measured. Plasma nitrite, cortisol, metHb and NMR increased directly with increasing ambient nitrite concentration, while Hb content showed a progressive decline. Levels of plasma potassium, GOT and GPT of the eel exposed to 6.64 mM ambient nitrite were significantly higher than the control fish. The activity of SOD and CAT in plasma, gill and liver of the eel following exposure to nitrite were augmented by increasing ambient nitrite. Levels of plasma nitrite, metHb, NMR, cortisol, glucose and antioxidative enzyme activities of the eel exposed to 2.33 mM ambient nitrite were significantly higher than the control fish. This study suggested that the eel acutely exposed to elevated ambient nitrite causes nitrite-induced stress responses, changes in antioxidative enzyme activities and hematological parameters.

• Journal of Power Electronics
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• 제15권4호
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• pp.1085-1092
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• 2015

In this paper, the expressions of the estimated information of a single-phase enhanced phase-locked loop (EPLL), when input signal contains harmonics and a DC offset while the fundamental component takes step changes, are derived. The theoretical analysis results indicate that in the estimated information, the n^th-order harmonics cause n+1^th-order periodic ripples, and the DC offset causes a periodic ripple at the fundamental frequency. Step changes of the amplitude, phase angle and frequency of the fundamental component cause a transient periodic ripple at twice the frequency. These periodic ripples deteriorate the performance of the EPLL. A hybrid filter based EPLL (HF-EPLL) is proposed to eliminate these periodic ripples. A delay signal cancellation filter is set at the input of the EPLL to cancel the DC offset and even-order harmonics. A sliding Goertzel transform-based filter is introduced into the amplitude estimation loop and frequency estimation loop to eliminate the periodic ripples caused by the residual input odd-order harmonics and step change of the input fundamental component. The parameter design rules of the two filters are discussed in detail. Experimental waveforms of both the conventional EPLL and the proposed HF-EPLL are given and compared with each other to verify the theoretical analysis and advantages of the proposed HF-EPLL.

• 한국해양바이오학회지
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• 제5권4호
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• pp.46-50
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• 2011

Phytoplankton forms the base of sea ecosystems. Various environmental factors and anthropogenic pollution, primarily, affect the concentration and photosynthetic activity algal cells, and the changes in the phytoplankton photosynthesis influence other elements of aquatic ecosystems. The increase in anthropogenic pollution markedly damages natural aquatic ecosystems, particularly, in the coastal zones, where an intense blooming of microalgae occurs, including the release of highly dangerous ecotoxic substances of various chemical natures (red tides). In this study, we tried to apply as a parameter for the algal blooming prediction in the ocean from fluorescence values in the taken samples around Busan coastal area. F0 value was almost constant but Fv/Fm value showed the irregular pattern. We presume that these results are due to the changes of the ocean environment and climate. To predict or give early warning the algal blooming, we need to investigate the specific area or fixed area through real-time monitoring. Especially, algal blooming prediction or warning can be achieved via continuously monitoring and interpretation of fluorescence changes.

• 농업과학연구
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• 제48권3호
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• pp.629-642
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• 2021

Land-use change has an important role in the hydrologic characteristics of watersheds because it alters various hydrologic components such as interception, infiltration, and evapotranspiration. For example, rapid urbanization in a watershed reduces infiltration rates and increases peak flow which lead to changes in the hydrologic responses. In this study, a physical hydrologic model the soil and water assessment tool (SWAT) was used to assess long-term continuous daily streamflow corresponding to land-use changes that occurred in the Naesungchun river watershed. For a 30-year model simulation, 3 different land-use maps of the 1990s, 2000s, and 2010s were used to identify the impacts of the land-use changes. Using SWAT-CUP (calibration and uncertainty program), an automated parameter calibration tool, 23 parameters were selected, optimized and compared with the daily streamflow data observed at the upstream, midstream and downstream locations of the watershed. The statistical indexes used for the model calibration and validation show that the model performance is improved at the downstream location of the Naesungchun river. The simulated streamflow in the mainstream considering land-use change increases up to -2 - 30 cm compared with the results simulated with the single land-use map. However, the difference was not significant in the tributaries with or without the impact of land-use change.

• 한국공간구조학회논문집
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• 제23권3호
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• pp.105-113
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• 2023

The study used the whole-life carbon assessment method to conduct a thorough carbon-neutral evaluation of a standard steel structure. To further assess carbon emissions, 11 design-changed models were evaluated, with changes made to the span between beams and columns. The results of the carbon emission assessment showed savings of approximately 13.1% by implementing the stage of the beyond life cycle. Additionally, the evaluation of carbon emissions through design changes revealed a difference of up to 42.2%. These findings confirmed that recycling and structural design changes can significantly reduce carbon emissions by up to 48.6%, making it an effective means of achieving carbon neutrality. It is therefore necessary to apply the stage of beyond life cycle and structural change to reduce carbon emissions.

• 전기전자학회논문지
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• 제18권2호
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• pp.272-281
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• 2014

전기 임피던스 단층촬영법을 이용한 정적 영상 복원에서 대표적으로 사용되고 있는 복원 알고리즘은 modified Newton-Raphson(mNR) 알고리즘으로 수렴 속도 및 추정 정확도 측면에서 비교적 다른 알고리즘들에 비해 좋은 성능을 나타낸다. mNR 알고리즘에서는 측정 전압과 계산 전압과의 차이, 즉 잔류오차를 최소화하도록 목적함수를 설정하고 이를 반복 연산하여 내부의 저항률 분포를 추정한다. 이때 EIT 역문제의 비정치성을 완화시키기 위해 조정방법을 사용하며 조정인자에 따라 서로 다른 영상 복원 성능을 나타낸다. 기존 기법에서는 반복 연산마다 일정한 상수 값의 조정인자를 사용하기 때문에 대상 물체의 내부 상태가 변하거나 측정 잡음 등이 있는 경우 때때로 조정인자에 따라 영상 복원이 수렴되지 않는다. 따라서 본 논문에서는 영상 복원 수렴 및 성능을 개선하기 위하여 잔류오차에 기반하여 반복 연산마다 자동적으로 조정인자를 수정하는 기법을 제안하였다. 시뮬레이션과 실험을 수행하여 제안된 기법의 영상 복원성능을 평가한 결과 비교적 양호한 성능을 나타내었다.