• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.12
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• pp.1926-1933
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• 2022

Parameterized multichannel Wiener filter (PMWF) is a linear filter that can control the trade-off between residual noise and signal distortion using the embedded parameter. To apply the PMWF to noisy inputs, accurate noise estimation is important and multichannel minima-controlled recursive averaging (MMCRA) is widely used. However, in the case of the MMCRA, the accuracy of noise estimation decreases when a directional interference is involved into the array inputs. Consequently, the performance of the PMWF is degraded. Therefore, we propose a noise power spectral density (PSD) estimation method for the PMWF in this paper. The proposed method is based on a consecutive process of eigenvalue decomposition on noisy input PSD, estimation of the target component contribution using directional information, and exponential weighting for improved estimation of the target contribution. For evaluation, four objective measures were compared with the MMCRA and we verify that the PMWF with the proposed noise estimation method can improve performance in environments where directional interfereces exist.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.571-581
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• 1995

The generation, verification and validation of Emergency Procedures for Nuclear Power Plant is a difficult and complex process. Atomic Energy Control Board(AECB) requires that emergency procedure and plan be produced before obtaining the Operating License, that is, detailed plans and procedures to handle emergency situations for both on-site actions and off-site actions be developed. In this report Emergency Operating Procedures Standard for Canadian Nuclear Utilities which makes reference to U. S. practices and the current direction of emergency procedures for CAN-DU reactors are reviewed and compared based on scope(events covered), methodology (event-oriented or symptom-oriented or hybrid) and format(method of presentation) preponderantly, and an attempt is made to integrate these procedures and as a result the recommended strategy for Wolsong unit 2, 3, & 4 is presented as event-specific procedures, generic procedures(when event is not diagnosed) and whose format is combination of logic diagram and text.

• Food Science and Preservation
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• v.30 no.6
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• pp.929-943
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• 2023

This study analyzed the variation in vitamin K content in conger eel (Conger myriaster) caught off Tongyeong, Gyeongsangnam-do, Korea, focusing on the influence of size (large and small) and harvest period (monthly throughout 2021). We applied enzymatic extraction and HPLC-fluorescence methods for the analysis of vitamin K₁ (phylloquinone) and K₂ (menaquinone). The vitamin K content in conger eel varied significantly with size and harvest season (p<0.05). In large-sized samples, the phylloquinone content peaked in July (0.80±0.09 ㎍/100 g), while the highest menaquinone content was in May (0.79±0.11 ㎍/100 g). Conversely, in small-sized conger eels, the highest phylloquinone was found in December (1.94±0.15 ㎍/100 g), and the peak menaquinone level was in January (0.66±0.02 ㎍/100 g). The fat content was highest in July for large samples and in January for smaller ones. There was a positive correlation between fat and total vitamin K contents in conger eel (r=0.631, 0.667). Method validation and quality control measures ensured data reliability for vitamin K₁ and K₂ analyses. This study provides reliable information on the size and seasonal variations of vitamin K in conger eels, a staple in the Korean diet. This information is valuable for inclusion in Korea's national food nutrition database and for formulating future national health and nutrition policies.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.1-9
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• 2002

The purpose of this study is to maintain high efficiency and reasonable use of cool thermal storage systems operated in the domestic building sector. As the result of efficiency test from the five types of operated cool storage systems on the condition that COP ranges are 2.6 to 3.4 during the day time and 2.1 to 3.0 during the night time and it decreased by more than 30% of rated COP given 3.8 to 3.0. The Analysis of cool storage rate shows that only 3 (21.4%) systems out of 15 buildings hold to over 40% capacity for its total capacity. To prevent the decrease in operating efficiency, it should correct the malfunction of 3-way valve and expansion valve and the mistake of control values for schedule program and increase cooling tower capacity. In order to improve piping line, it needs bypass brine line off refrigerator, separation of chilled water line with Ice Slurry system at day and night time and speed control of chilled and warm water pumps. This study does require the more studies on improving difficulty of increasing cooling load with Ice on Coil system, waterproofing with Ice Ball system, COP drop during the night time with Ice Lens, low operating temperature during the day time with Ice Slurry and increasing of Power loss due to hot gas de-icing with Ice Harvest in the future.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.257-264
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• 2009

The purpose of this study was to examine the effects of the game application learning 8th graders' scientific attitude, which was utilized as a strategy to improve the teaching skills and methods in the lesson of 'the history of the earth and diastrophism'. The subjects of this study were 120 students of 8th grade at a middle school located in a metropolitan city in Korea. To start off with homogeneity of a group, this study recruited participants by the results of a diagnostic test taken early in the year and a mid-term examination taken at the end of April. As a result, a total of 4 male classes that showed similar results on the two tests were selected and divided into two groups: one in experimental and the other in control. In addition, the top 20% students and the low 20% students were chosen for comparison of their scientific attitudes based on the results of the mid-term examination. The traditional teachings were offered to the control groups while the experimental lessons with the game activities performed at the stages of application and summary in teaching were offered to the experimental groups over 10 periods. Results of the pre- and post-test on the students' scientific attitude demonstrated that there was a statistical significance between the two groups, which suggested that the experimental group showed a meaningful improvement in the scientific attitude after experimental intervention lesson activities with game applications. Also, the more meaningful improvement in the scientific attitude was found in the lower group than in the higher group. It implies that lessons with the game activities motivated the students to voluntarily participate in school science learning by enhancing their interests. Therefore, it is suggested that game application learning be a new teaching-learning material that helps to encourage learners to actively participate in middle school science learning.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.77-88
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• 2000

In this paper, the 3-mode variable gain high power amplifier for a transmitter of INMARSAT-B operating at L-band(1626.5-1646.5 MHz) was developed. This SSPA can amplify 42 dBm in high power mode, 38 dBm in medium power mode and 36 dBm in low power mode for INMARSAT-B. The allowable errol sets +1 dBm as the upper limit and -2 dBm as the lower limit, respectively. To simplify the fabrication process, the whole system is designed by two parts composed of a driving amplifier and a high power amplifier. The HP's MGA-64135 and Motorola's MRF-6401 were used for driving amplifier, and the ERICSSON's PTE-10114 and PTF-10021 for the high power amplifier. The SSPA was fabricated by the RP circuits, the temperature compensation circuits and 3-mode variable gain control circuits and 20 dB parallel coupled-line directional coupler in aluminum housing. In addition, the gain control method was proposed by digital attenuator for 3-mode amplifier. Then il has been experimentally verified that the gain is controlled for single tone signal as well as two tone signals. In this case, the SSPA detects the output power by 20 dB parallel coupled-line directional coupler and phase non-splitter amplifier. The realized SSPA has 41.6 dB, 37.6 dB and 33.2 dB for small signal gain within 20 MHz bandwidth, and the VSWR of input and output port is less than 1.3:1. The minimum value of the 1 dB compression point gets more than 12 dBm for 3-mode variable gain high power amplifier. A typical two tone intermodulation point has 36.5 dBc maximum which is single carrier backed off 3 dB from 1 dB compression point. The maximum output power of 43 dBm was achieved at the 1636.5 MHz. These results reveal a high power of 20 Watt, which was the design target.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.306-312
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• 2013

The purpose of this study was to evaluate the physicochemical and sensory characteristics of white bread and added 2%, 4%, 6%, or 8% Hallabong powder. Dough pH of the control group was 5.65, and it decreased as increasing amounts of Hallabong powder were added. Also, total titratable acidity of dough significantly increased with increases in Hallabong powder. The fermentation power and dough expansion significantly increased with increasing incubation time; the control was highest at 98.67%. White bread pH, specific volume, and baking loss decreased significantly as with increased Hallabong powder content. The bread moisture content was not significantly different between samples, differing only from 40.61~41.83%. Water activity was 0.960 Aw in the 6% Hallabong powder mixture, which was the highest in samples. In color, lightness of crust significantly decreased with increased Hallabong powder content, whereas redness showed the reverse effect. Lightness of crumbs significantly decreased, with increased Hallabong powder content, whereas redness and yellowness showed the reverse effect. In texture, hardness and fracturability significantly increased, while resilience showed the reverse effect. In the sensory evaluation, citrus flavor, bitterness, astringency, and off-flavor significantly increased with increased Hallabong powder content, and the control sample showed the highest score in color, flavor, softness and overall acceptability. The 2% and 4% samples showed more than average scores. Based on these results, Hallabong powder could be considered a functional material. The optimum amount of Hallabong powder to add for baking bread would be 2~4%.

• Journal of Life Science
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• v.28 no.10
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• pp.1179-1185
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• 2018

Recently, Sargassum horneri, the marine weed inhabiting the shoreline, beach, and littoral sea area, has caused serious damage to intensive aquaculture farms particularly those around Jeju Island, South Korea. The purpose of this study was to investigate the diversity of microorganisms in Sargassum horneri and to provide basic data on ecological problems by identifying microbial functions. A total of 88 isolates were identified by 16S rRNA sequencing. Proteobacteria was the dominant phylum accounting for 88%, including class ${\alpha}-proteobacteria$, six genera, and ten species. The dominating genus, Pseudobacter, accounted for 40% in Pseudorhodobacter, 20% in Paracoccus, and the remaining at 10% each were Rhizobium, Albirhodobacter, Skermanella, and Novosphingobium. Class ${\beta}-proteobactera$ included five genera and ten species. Genus Hydrogenophaga accounted for 50%, while genus Azoarcus accounted for 20%, and the remaining Oxalicibacterium, Duganella, and Xenophilus were 10% each. Class ${\gamma}-proteobacteria$ with 13 genera and 57 species, accounted for 74% in phylum Proteobacteria, 23% in Shewanella, 19% in Cobetia, 12% in Pseudomonas, 4% each in Vibrio and Serratia, and 2% each in Rheinheimera, Raoultella, Pantoea, Acinetobacter, Moraxella, and Psychrobacter genera. In addition, Actinobacteria with two species of Nocardioides genera accounted for 50%, and Bacteroidetes accounted for 33%, with three genera and five species that included Lacihabitans and Mariniflexile. The remaining Dyadobacter, Cellulophaga, and Ferruginibacter genera each accounted for 11%.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.319-328
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• 2003

The purpose of this paper is to develop a medical laser system using the semiconductor diode laser in order to photodynamic cancel therapy as a light source. The ideal light source for photodynamic therapy would be a homogeneous nondiverging light with variable spot size and specific wavelength with stability. After due consideration in this point, in this paper, we used a diode laser resonator of 635nm wavelength. The development laser system have a statistical laser out beam with accuracy control using the constant current control of method and clinic-friendly with compact. In order to protect the diode resonator from the over-current, the rush-current and electrical fault, we specially designed. The most importance therapeutic factor are the radiation mode for cancer therapy. So we developed the radiation mode of CW(Continuous Wave), long pulse, short pulse, and burst pulse and can adjust the exposure time from several milli-second to several minute. The experimental result shows that laser beam power was increased linear from 10mW to 300mW according to the increasing input current and the increasing exposure time. The developed new compact diode laser system have a stability of output power and specific wavelength with easy control and transportable for many applications of PDT.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.175-181
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• 2013

These studies were identified the effect of four types of non-perforated breathable (NPB) packing film and three sizes on storage ability of fresh-cut for ready to eat packaging at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days storage in Salicornia herbacea. The fresh weight loss was less than 2% in every films at $5^{\circ}C$ condition after 25 days storage, and the $10^{\circ}C$ also had same result on 15 days storage except 100,000 cc NPB film. Compare with storage after 15 days, storage condition at $5^{\circ}C$ had shown better result under the 1% fresh weight loss rate. The 5,000 cc and $5^{\circ}C$ condition had been shown the characteristics of MA packaging in carbon dioxide and oxygen concentrations. The ethylene concentration in vacuum film was higher 10 to 100 times than in NPB film treatments during storage. But ethylene concentration was not statistically significant differences among size treatments. Every conditions had been measured the anti-oxidant activity by DPPH method after storage at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days. S. herbacea at $5^{\circ}C$ had been more than twice of activity compare with that at $10^{\circ}C$. 100,000 cc NPB film had been higher contents of anti-oxidant activity at $5^{\circ}C$ and $10^{\circ}C$. As the fresh-cut sizes, 3 cm and 5 cm sizes had changed depending on film types but 10 cm were not effected by the film types in the DPPH activity. When panel test had been tried to measure the visual quality and off-flavor after storage, $5^{\circ}C$ with a filme of 5,000 cc treatment had established higher value than other treated conditions. As these results, it's may be suggested that the $5^{\circ}C$ with 5,000 cc non-perforated breathable film for MA storage in Salicornia herbacea at fresh cut distribution system. Fresh cut size 10 cm with 100,000 cc NPB film also had the good quality for 15 dyas storage at $10^{\circ}C$, and this result can be applied for short term distribution system in Korea.