• Journal of Astronomy and Space Sciences
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• 제40권4호
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• pp.131-148
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• 2023

Lunar permanently shadowed regions (PSRs) never see direct sunlight and are illuminated only by secondary illumination - light reflected from nearby topography. The ShadowCam imaging experiment onboard the Korea Pathfinder Lunar Orbiter is acquiring images of these PSRs. We characterize and discuss the nature of secondary illumination for the Shackleton PSR from ShadowCam radiance-calibrated images. We also use modeling to understand the magnitude and direction of the secondary illumination. Results from our analysis highlight the non-homogeneous, dynamic, and complex nature of PSR secondary lighting. Knowledge of the direction of the secondary illumination is crucial for reli-able interpretation of contrasts observed in ShadowCam images. This preliminary analysis of the floor of Shackleton crater from images acquired over multiple secondary illumination conditions does not reveal indications of exposed surface ice, even though temperatures are constantly below 110K.

• The Korean Journal of Ecology
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• 제19권4호
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• pp.305-320
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• 1996

It is necessary to obtain information about the productivity of the human-influenced forest and to understand the consumption of biomass resources in secondary forest in order to examine the resource flux by human activity in rural landscape. Thus the aims of this study were to elucidate the biomass and their use of secondary Pinus densiflora forests and to discuss sustainable utilization of secondary forests in rural landscape system. This study was carried out in Yanghwa-ri, Kongjugun, Chungcheongnam-do, central Korea. The changes of growth rate and aboveground biomass of a pine forest for 2 years were analyzed to understand forest management regimes in rural pine forests. Through allometric equations deduced from 25 sample trees, biomass was estimated. The biomass increase of pine forest was approximately 16.36 t/ha/yr in the unexploited stand and 12.24 t/ha/yr in the exploited stand. These were nearly equal to those of natural pine forests in central Korea. This result proved that human-influenced pine forest in rural landscape as well as the natural one has high potentiality to provide forest products. Making graveyard in forest-land was the important disturbance and land-use which currently occurring in rural landscape in the study area. Finally, we presented some forest management for stutainable and positive uses of secondary forests as one of the local energy resources in terms of the holistic landscape-ecological view.

• 오토저널
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• 제14권5호
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• pp.95-106
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• 1992

Active control of acoustic noise is an application area of adaptive digital signal processing with increasingly interest along the last year. This work studies the implementation of the multichannel LMS filter and the application of this algorithm for the reduction of the noise inside a vechicle cabin using a number of 'secondary sources' drived by adaptive filtering of a reference noise source. Firstly, we propose the use of an adaptive method for the time-varient optimal convergence factor. Secondly, we propose the use of adaptive delayed inverse model to estimate the elastic-acoustic transfer function presented in vechicle cabin. The original, primary source is often periodic, with a known fundamental frequency. A suitably filtered reference signal can thus be used to drive the secondary sources. An algorithm is presented for adapting the coefficients of an FIR filter feeding such a secondary source in such a way as to minimize the output of a suitably placed microphone. In this algorithm, the coefficients of adaptive filter driving an array of secondary sources can be adapted to minimize the sum of the squares of the outputs of a number of error microphones. The multichannel LMS algorithm displays that such an algorithm is considered suitable to used for the global suppression of noise in vehicle cabin.

• 한국산림과학회지
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• 제97권5호
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• pp.501-507
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• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.177-181
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• 2001

The conversion efficiency of a cesium iodine coated micro-channel plate is studied. We use the EGS4 code to transport photons and generated electrons until their energies become less than 1keV and 10keV respectively. Among the generated electrons, the emission from the secondary electrons located within the escape depth of 56nm from the photo-converter boundary is estimated by integrating the product of the secondary electrons with a probability depending only on their geometric locations. The secondary electron emission from the generated electrons of energy higher than 100eV is estimated by the 'universal yield curve'. The sum of these provides an estimate for the secondary electron yield and we show that results of applying this algorithm agree with known experimental results. Using this algorithm, we computed secondary electron emissions from a micro-channel plate used in a gas electron multiplier detector that is currently being developed at Korea Atomic Energy Research Institute.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.538-544
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• 2010

This paper proposes an estimation algorithm for the separate primary and secondary leakage inductances of a three phase $Y-\Delta$ transformer using least squares method. The voltage equations from the primary and secondary windings are combined into a differential equation to estimate the separate primary and secondary leakage inductances in order to use the line current of the delta winding. Separate primary and secondary leakage inductances are obtained by applying least squares method to the differential equation. The performance of the proposed algorithm is validated under transient states, such as magnetic inrush and overexcitation, as well as in the steady state with various cut-off frequencies of low-pass filter. The proposed technique can accurately generate separate leakage inductances both in the steady and transient states.

• 한국환경교육학회지:환경교육
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• 제22권3호
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• pp.112-124
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• 2009

Visual images are important elements of the communication of environment in secondary school environment textbooks, which dominate classroom approaches to teaching and learning. This study was to analysed the perspectives of pedagogical and social-pedagogic of visual images in 'global warming' unit of six different Korean environment textbooks. Analysis makes use of the dimensions pedagogical functions, content specialization, social-pedagogic relationships, and abstraction of the visual codes. The results showed that most of the visual images in school environment textbooks tend to establish social-pedagogic relationships with students. The results of our study have implications for textbook authors and secondary environment teachers. We suggest that future studies may focus on students' and teacher's interpretation of visual images new secondary environment textbooks.

• 산업경영시스템학회지
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• 제21권45호
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• pp.145-154
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• 1998

The effects of secondary task on driving performance and subjective workload were investigated during a simulated driving. The driving performance was determined by the appropriateness of break timing. The driving simulator was provided by the Korea Road Traffic Safety Association. The subjective workload was tested by using a multidimensional measure such as NASA-TLX. Road was categorized into two types: narrow alley and wide street. The secondary task included pushing the number on the cellular phone, pushing radio channel, and conversing with a passenger. Seventeen subjects volunteered in the study. The data were analyzed by using SAS. Results showed that using the cellular phone and pushing channel during driving caused 3∼22% decline of driving performance and 42∼59% increase of subjective workload respectively. These results indicated that the secondary task could be potentially dangerous although there was not a significant performance decrease due to the notable increase of mental workload. In the future, if we can use a more sensitive and realistic driving simulator, the effects of secondary task under a dynamic driving situation can be investigated.

• 한국임상약학회지
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• 제23권2호
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• pp.142-150
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• 2013

Background: Secondary hyperparathyroidism (SHPT) is common in patients with chronic kidney disease, affecting most of those who are receiving dialysis. Cinacalcet, a novel calcimimetic, targets the calcium-sensing receptor to lower PTH levels in dialysis patients. Objective: This study aimed to assess efficacy, safety and appropriateness of use of cinacalcet in dialysis patients. Method: This retrospective study was performed on total 24 cases with identified intact parathyroid hormone (iPTH), serum calcium and phosphorus levels before and 4 weeks after cinacalcet initiation at a teaching hospital from July 1st, 2011 to October 31st, 2012. Results: Cinacalcet decreased iPTH by 19% from baseline after 4weeks treatment and it was statistically significant (p<0.001). Cinacalcet also significantly decreased iPTH levels regardless of dialysis modality (hemodialysis group versus peritoneal dialysis group) and severity of SHPT (iPTH 300-800 pg/ml group versus iPTH >800 pg/ml group). Serum calcium, phosphorus and Ca x P levels were decreased without statistical significance. Gastrointestinal events, headache and hypocalcemia were the most common side effects. Monitoring for iPTH and serum calcium was not performed appropriately. 43.7% patients initiated cinacalcet therapy at serum calcium level< 9.0 mg/dl. Conclusion: In conclusion, cinacalcet lowers parathyroid hormone levels with no serious side effects. However, it is required to avoid cinacalcet treatment in patients with low serum calcium levels and monitor iPTH and serum calcium levels during cinacalcet administration.

• 간호행정학회지
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• 제18권4호
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• pp.402-413
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• 2012

Purpose: This study was done to explore factors related to amount of service use for elders with long-term care needs. Methods: A descriptive-correlation design was used. The sample included 259 elders and their primary caregivers who had cared for the elders for at least 6 months. Data on long-term care need assessment, service use and interviews with primary caregivers were analyzed. Results: There was no significant relationship between the sociodemographic characteristics and the amount of services use. Amount of service use differed significantly by Long-term care classification. The mean scores for class 1, 2 and 3 were 22.68, 21.47 and 17.87 days respectively. Primary caregiver relationship with the elders and the number of family-friend helpers were also significant. Multivariate regression analysis showed that gender, marital status, activities of daily living, cognitive impairment, and secondary caregiver support explained 17% of the total variance of service use among these elders (F=3.50, p<.001). Conclusion: The results of this study indicate that critical factors including secondary caregiver support and individual background, and other functional dependencies except for physical function should be considered in accurately predicting the amount of service use for community dwelling elders with long-term care needs.