• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.617-631
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• 2002

This study has examined 5-year students in the kindergarten and students in the 2nd, 4th, and 6th grade in the primary school to analyze their perceptions about scientists. science, and how they apply science in their daily lives. First, students have 4 stereotypic images on scientists, specifically in 'indoor', 'male', 'lab coat'. and 'scientific instrument'. There were significant differences in stereotypic images on scientists depending on genders and ages. Girls and primary students showed higher scores than boys and kindergarten students did. respectively, in stereotypic images on scientists. No differences were observed for the stereotypic images on scientists among primary students, regardless of their grades. Second, most of students were interested in science. Depending on grades, there were significant differences in their preference for science. Students in higher grades showed lower scores than those in lower grades did. In addition, only a few of them hoped to be a scientist in the future. Boys showed higher scores in their hope to be a scientist in the future than girls did. The students in lower grades showed higher scores than those in higher grades. Third, most of children thought themselves doing activity-oriented science in school. Outside school, however, they did not use the knowledge and skills they had learned for science in school. Students in the primary school showed more concept-oriented perception for science than those in kindergarten did. This perception was gradually increased as the grades of the students go up.

• Journal of Aquaculture
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• v.20 no.1
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• pp.1-6
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• 2007

Two feeding experiments were conducted to investigate the effects of fermented cactus fruit (Opuntia ficusindica) fluid (FCFF) as a feed additive to a commercial diet on the growth of red sea bream, Pagrus major, and to determine an effective dose. FCFF was prepared by mixing crushed cactus fruit with a starch solution and commercially available microorganisms for 2 weeks at room temperature. Three triplicate groups of red sea bream had initial mean weights of 84.1 g (Exp-1) and 5.1 g (Exp-2) and were fed experimental diets containing 0%, 1%, and 5% FCFF for 2 months (Exp-1) and 0%, 0.2%, 0.5%, and 1% FCFF for 3 months (Exp-2), respectively. In experiment 1, the mean body weight of fish fed the diet containing 1% FCFF was significantly higher (P<0.05) than that of fish fed the diet without FCFF. The survival rate was highest in fish fed the diet containing 1% FCFF, although the difference was not statistically significant. The feed gain ratio (FGR), specific growth rate (SGR), and condition factor (CF) values of fish fed the diet containing 1% FCFF were higher than those of fish in the other dietary groups that received lower levels of FCFF. The daily feeding rate (DFR) of fish fed the diet containing 1% FCFF was slightly lower but not statistically different than the DFR values of fish in the other dietary groups. In experiment 2, the final mean body weight of fish fed the diet containing 1% FCFF was significantly (P<0.05) higher than the mean weight of fish in the control group. The FGR, SGR, and CF values of fish fed the diet containing 1% FCFF were better than the values from fish in the other dietary groups that received lower levels of FCFF, although the differences were not statistically significant. However, the DFR of fish fed the diet containing 1% FCFF was lower than those of fish in the other groups. These results suggest that FCFF could be used as a feed additive in commercial fish food and a preferable level of supplementation is at least 1.0% in fingerling and young red sea bream.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.33-42
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• 2020

This study identified the substitution of /u/ for /o/ (e.g., pyəllo [pyəllu]) in Korean based on the speech corpus as a function of grammar items. Korean /o/ and /u/ share the vowel feature [+rounded], but are distinguished in terms of tongue height. However, researchers have reported that the merger of Korean /o/ and /u/ is in progress, making them indistinguishable. Thus, in this study, the frequency of the phonetic manifestation /u/ of the underlying form of /o/ for each grammar item was calculated in The Korean Corpus of Spontaneous Speech (Seoul Corpus 2015) which is a large corpus from a total of 40 speakers from Seoul or Gyeonggi-do. It was then confirmed that linking endings, particles, and adverbs ending with /o/ in the word-final position were substituted for /u/ approximately 50% of the stimuli, whereas, in nominal items, they were replaced at a frequency of less than 5%. The high rates of substitution were the special particle "-do[du]" (59.6%) and the linking ending "-go[gu]" (43.5%) among high-frequency items. Observing Korean pronunciation in real life provides deep insight into its theoretical implications in terms of speech recognition.

• Korean Journal of Social Welfare
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• v.62 no.1
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• pp.317-342
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• 2010

The purpose of this study is to investigate daily lives of the intellectually disabled living in residential facilities. The daily time use method that monitors and records 24 hours of the subject was used for the analysis of daily lives of the institutionalized disabled and verbal interaction patterns within each facility. In particular, the analysis focused on 'frequency of activities' and 'lives', with the method of time budget. Based on the activity category table of the 2004 nationwide Time Use Survey, the analysis aimed to identify differences and similarities between the non-disabled and the disabled in terms of daily time use. The interaction pattern analysis method on grounds of the Flanders Category system(1963) indicates the level, the type, and the full details of interaction between the institutionalized disabled and the living rehabilitation teachers. This study is all the more significant in that it monitored the daily lives of the institutionalized disabled for the first time to allow in-depth understanding about the daily lives of the disabled; analyzed interaction patterns between the institutionalized disabled and living rehabilitation teachers; applied time budget study method, a frequently used one in adjacent fields, and therefore should serve as a valuable source material for future studies.

• Korean Journal of Social Welfare
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• v.62 no.1
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• pp.263-289
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• 2010

This study did by purpose to be utilized to basic data for elevation of human rights consciousness of homeless facilities employees through examining their human rights consciousness by investigating human rights sensitivity that can grasp degree of human rights consciousness of homeless facilities employees. The human rights sensitivity of 390 homeless facilities employees who are working at 38 facilities around the whole country is compared and investigated. As a result, human rights sensitivity of employees displayed very low score by average 64.55 points in total score 150 points. Human rights sensitivity academic career of employees was shown meaningful difference, and human rights consciousness of substantial administrator is appeared very low in human rights sensitivity by duties. According to the existence and nonexistence of human rights education at the homeless facilities, the employs who had got human rights education shows higher human rights sensitivity than the employs who had not go human rights education. Therefore, regular program that can enforce human rights education Collectively as a formal curriculum in homeless facilities should be established and it's proposed to develop practical and efficient human rights education manual case by case related with the violation of human rights.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.747-751
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• 2010

The objective of this research were to produce amino acids from freezing-dried brown seaweed(Undaria pinnatifida) powder by sub- and supercritical water hydrolysis and to characterize the products. The hydrolysis was carried out in a batch type reactor consisting of 4.6 cm inside diameter and $200cm^3$ vessel and stir made of Hastelloy 276. A stir inside the reactor was continuously moving at 100 rpm. Brown seaweed powder and 100 mL of 1% acetic acid in distilled water were charged into the reactor at a ratio of 1:100(w/v). The applied conditions were $180{\sim}374^{\circ}C$, respectively for 1 hour. The total amino acid content was found to be significantly higher in brown seaweed hydrolyzed by low temperature comparing to high temperature. The amounts of low molecular weight amino acids(glycine, alanine, serine etc) were higher than that of high molecular weight amino acids. The maximum yields of amino acids were produced at low temperature($220^{\circ}C$) with acid catalyst.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1104-1109
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• 2005

In this paper, a Ka-band harmonic mixer is designed and fabricated on the base of the multiplier theory that there is a bias point to maximize the third harmonic order($3f_{LO}$) with respect to a fundamental LO frequency($f_{LO}$), which can make the high-order mixing element($f_{RF}{\pm}3f_{LO}$) to be greater than other mixing elements, Pumping a RF frequency($f_{RF}$) and LO frequency($f_{LO}$). The harmonic mixer by the proposed design method is fabricated by using a commercial GaAs MESFET device with a plastic package and overcome these disadvantages that a conventional mixer in Ka-band suffer from a high cost, inefficient productivity and circuit complexity. The harmonic mixer have a -10 dB conversion loss at the IF Sequency($3f_{LO}-f_{RF}$=1.0GHz) by selecting a gate bias voltage for the maximum third-order LO harmonic element($3f_{LO}$=34.5 GHz) as pumping LO frequency($f_{LO}$=11.5 GHz) With respect to RF Sequency ($f_{RF}$=33.5GHz)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2A
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• pp.95-104
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• 2010

In wireless communication system, a variety of retransmission algorithms are used in order to improve the quality of service of users. But the system may be inefficient because retransmission algorithms operate independently with other layers. Also, the quality of service can be degraded due to the unnecessary retransmission of packets. To solve these problems, the study on the cross-layer retransmission schemes have been widely performed. However, in order to apply cross-layer retransmission schemes to wireless communication system, whether the performance of cross-layer retransmission schemes meets QoS requirements of each service class has to be verified. Thus, this paper proposes the mathematical model for analyzing the performance of the cross-layer retransmission schemes and derives both the suitable retransmission scheme and the optimal retransmission parameter on each service class. The proposed mathematical model selects the MCS level based on channel state information and The performance analysis is comparatively easy in case that HARQ, ARQ, and AMC schemes are combined. The proposed mathematical model also enables the analysis of the packet transmission delay. To utilize the analytical model, this paper derives the suitable retransmission scheme and the optimal retransmission parameter for delay sensitive services in WiMAX system. Also, the proposed analytical model can be used to analyze the performance of wireless communication system such as LTE and WLAN.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.61-67
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• 2020

ESS-based buildings are being widely studied as an effective methods for saving energy with ZEB, BEMS, and FEMS. However, in large scale buildings, there are many energy-consuming facilities, so it is necessary to identify important energy-consuming facilities to build a real-time measurement system. In addition, there are a myriad of factors that affect the dependent variable of energy use, therefore there is a limitation that effective energy management is difficult. Therefore, this study applied the measurement boundary setting methodology according to the energy supply status through due diligence for the demonstration ESS distribution logistics facility, and suggested the methodolgy for presenting priority for the construction of the measurement system. Afterwards, the impact variables that Acting as an independent variable affecting the energy consumption of the distribution and logistics facilities were categorized into intrinsic and meteorological variables. Lastly, all factors that could affect the energy consumption of the actual distribution and logistics facilities, were classified and presented as guidelines list. By applying the results of this study, it is possible to build a monitoring system at a low cost and high efficiency in a distribution and logistics facility with a complex structure. And by identifying the main independent variables for the measured energy consumption, effectively identifying trends in energy consumption and deriving saving points It is expected to be able to operate the ESS-based infrastructure.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.739-751
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• 2018

The purpose of this study is to identify the differences of argumentation discourses for Socio-Scientific Issues in the types of decision-making and personality traits of pre-service biology teachers. For this study, SSI discussion topics were selected according to four types of decision making: logical reasoning, suggestion of complement, emotional base, and internal conflict. Three groups were constructed based on personality traits such as extroversion, acceptability, and integrity. Each three group used the workbook specially developed and freely used the smart device for discussion. A recorder and a camcorder were used to record each group, their behavior was recorded and the written materials during the discussion were collected for the results. Using Walton's analysis framework, the collected data analyzed in terms of the source of utterance, the process of dialogue shift, and the critical movements that can judge the reasoning of utterance. As a result of the study, it was confirmed that the decision-making type of SSI topics and learners' personalities were influential in the decision-making process of SSI small group discussions. This research shows that there is a need to develop instructional materials considering decision-making types and learners' personality types of students as well as pre-service teachers for SSI discussion.