• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.141-152
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• 2020

The rapid on-site measurement of hydroponic nutrients allows for the more efficient use of crop fertilizers. This paper reports on the development of an embedded on-site system consisting of multiple ion-selective electrodes (ISEs) for the real-time measurement of the concentrations of macronutrients in hydroponic solutions. The system included a combination of PVC ISEs for the detection of NO₃, K, and Ca ions, a cobalt-electrode for the detection of H₂PO₄, a double-junction reference electrode, a solution container, and a sampling system consisting of pumps and valves. An Arduino Due board was used to collect data and to control the volume of the sample. Prior to the measurement of each sample, a two-point normalization method was employed to adjust the sensitivity followed by an offset to minimize potential drift that might occur during continuous measurement. The predictive capabilities of the NO₃ and K ISEs based on PVC membranes were satisfactory, producing results that were in close agreement with the results of standard analyzers (R² = 0.99). Though the Ca ISE fabricated with Ca ionophore II underestimated the Ca concentration by an average of 55%, the strong linear relationship (R² > 0.84) makes it possible for the embedded system to be used in hydroponic NO₃, K, and Ca sensing. The cobalt-rod-based phosphate electrodes exhibited a relatively high error of 24.7±9.26% in the phosphate concentration range of 45 to 155 mg/L compared to standard methods due to inconsistent signal readings between replicates, illustrating the need for further research on the signal conditioning of cobalt electrodes to improve their predictive ability in hydroponic P sensing.

• Korean Journal of Social Welfare
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• v.58 no.1
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• pp.425-456
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• 2006

This study investigated the adaptation process of abused children in long-term foster care and the stages of adaptation process. Also, this study aimed to find the factors influencing the adaptation of abused children in long-term foster care and to examine the relationships between the adaptation process in long-term foster care and the recovery of aftereffect of the abused children. The researchers tried to find the factors influencing the possibilities about the return of their biological parents' home. The researchers used a purposeful sampling and interviewed three abused children and three parents in long-term foster care and two social workers. This study utilized grounded theory approach of Strauss and Corbin(1990) to analyze the interviewed data. Specifically, the researchers applied open coding, axial coding and selective coding from grounded theory approach to analyze the data. On the other hand, the researchers used Miles and Huberman(1994)'s time-ordered matrix and time-ordered network to investigate the categories influencing the adaptation process of abused children in long-term foster care. This study used interviewees, literatures, newspapers, and internet resources relating to abused children for triangulation of data. The researcher interviewed from October 15, 2004 to January 31, 2005. The total sessions of each person were consisted of two sessions for each person and the interview time of each session was one or two hours.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.279-285
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• 1998

Fenitrothion-degrading microorganisms were isolated from 124 sampling sites of paddy, upland, forest and polluted soil, and wastewater. A total of 1,071 strains were isolated from each selective medium supplemented with 50mg/l of fenitrothion - nutrient agar (NA) 601, potato dextrose agar (PDA) 201, Actinomycetes isolation agar (AIA) 168 and basal salt medium (BSM) 101, respectively. Twenty-eight effective strains of them, which showed more than 80% degradation of fenitrothion by the gasliquid chromatography(GLC) analysis. were successfully selected from each liquid culture supplemented with 50mg/l of fenitrothion - NB 12(upland soil 3, paddy soil 3, forest soil 2, polluted soil 4), PDB 8(upland soil 1, paddy soil 2, forest soil 2, polluted soil 3) and PSB 8(upland soil 1, forest soil 1, polluted soil 6), respectively. Four strains - NPal, NFol, PFol and BPol, which have the most powerful degradation activity were finally selected among 28 fenitrothion-degrading microorganisms based on the degradation rate at the concentration of 100mg/l fenitrothion in enrichment media.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1316-1321
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• 2000

Objectives : The authors analyzed the surgical series of Cushing's disease to evaluate the proper treatment policy and to verify the possible prognostic factors. Material and Methods : Of 50 patients diagnosed as Cushing's disease and operated at Department of Neurosurgery of our institute between 1988 and 1999, 48 patients with available medical records were analyzed retrospectively. Mean follow-up period was 48 months(3 to 109 months). Preoperative diagnosis was made after evaluating the patients with multiple-stage endocrinological studies and 31 selective patients were evaluated with inferior petrosal sinus sampling(IPSS). Magnetic resonance imaging(MRI) and/or high resolution computerized tomography(CT) was done in all patients. A total of 51 transsphenoidal adenomectomy(TSA) were performed including 3 revision for initial surgical failure cases. Remission was decided on the basis of both endocrinological criteria and clinical status. Radiation and/or ketoconazole therapy were applied to failed cases. For the verification of prognostic factors, the authors evaluated the statistical significance of multiple variables over remission rate by chi-square test. Result : Sensitivity of IPSS for central localization was 93.5% which was better than that of MRI(87.5%). But for lateralization, it was 72.4% for IPSS versus MRI 90.5%. Success rate of TSA was 82%(42/51) and recurrence rate was 9%(4/48). When including adjuvant treatments for surgically failed cases, overall success rate was 89.6% and all of 3 reoperated cases(TSA) due to recurrence were successful. Significant complication occurred in 7.8%(4/51) after TSA including hypopituitarism, diabetes insipidus, and visual loss. Non-existence of tumor in MRI and prolonged symptom duration(>3 years) were significant prognostic factors. Conclusion : TSA can be considered as initial treatment for Cushing's disease. In surgically failed cases, multiple treatment modality may improve the overall outcome and repeated TSA for recurrent cases seem to provide similar success.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.603-618
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• 2019

This study aims to explore the meaning and nature of the nursing experience of visiting nurses of home-based long-term care service centers by using van Manen's hermeneutic phenomenological approach. A total of 10 home-visiting nurses working in Seoul and Gyeonggi-do Province were recruited through purposive, convenience, and snowball sampling and participated in the study. Data were collected from January 7, 2017 to October 12, 2018 through in-depth individual interviews with the participants. The analysis resulted in 6 essential themes regarding the lived experience of visiting nurses: 'establising a good rapport with the patient and his or her family caregiver', 'building the foundation of visiting nursing by performing autonomously nursing procedures for the patient', 'facing the reality not to be able to work as much as I want due to the limitations of the support system in performing work as a visiting nurse', 'upset when sincerity could not be delivered', 'following the calling of medical personnel by taking responsibility for 'my patient', and 'pledging oneself to career-long work, feeling reward as a visiting nurse.' The findings of the study help understand the role and importance of visiting nurses and contribute to the preparation of practical measures to improve the quality of home-visiting nursing.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.369-377
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• 2017

The purpose of this study was to investigate high school students' perceptions on chemistry subjects: reasons for choosing chemistry, learning volume and content difficulty, interests, teaching/learning methods, preferable classes etc. A total of 1,087 students who took chemistry subjects at 126 high schools by proportional stratified sampling were voluntarily participated in the survey. The main reasons the students chose chemistry subjects were interests and interests in chemistry, foundation to science, relevance to college majors, and so on. Students recognized that the learning volume and content difficulty as normal level was about 60%. Reasons why chemistry was difficult was that, although there was a difference in degree, chemistry was difficult in itself and had too much things to memorize. In the case of interests in chemistry subjects, students of 43.9% of Chemistry I and 52.0% of Chemistry II recognized the level as normal. The reason why not interested in chemistry subjects was that it was the nature of chemistry contents, or students had neither interests and enjoyment of chemistry nor foundation for chemistry. Classes were mostly lectures but the students preferred mainly experimental activities, or explanation with real-life examples or science stories. The frequency of experimental activities was found to be 1 to 5 times per semester, or not experimented. Research and efforts will be necessary to improve classes and environments for students' experimental activities.

• Journal of Mushroom
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• v.17 no.3
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• pp.167-170
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• 2019

Cultivation of brown mushrooms, rather than that of white variants is preferred by Korean mushroom farmers, as the former are resistant to diseases. However, brown mushrooms were cultivated only in selective eco-friendly agricultural farms due to lack of consumer awareness. After providing information about brown mushrooms to respondents through a 1-minute video clip, a survey was conducted on social network service (SNS) to assess recognition and preference for brown mushrooms. A food evaluation was then conducted among 200 people randomly selected from the survey respondents. Most respondents (83%) had not encountered brown button mushrooms previously, and 98% of the respondents were willing to buy these mushrooms because they were "curious about its taste" (44%). In the food evaluation, 32% of the respondents found the brown button mushrooms to be delicious, 28% reported a good flavor, and 31% described a good texture. In addition, we confirmed that 95% of respondents were interested in purchasing brown mushrooms after sampling. Therefore, in the present study, we evaluated public perception, preference, and taste of brown button mushrooms, and confirmed that availability of information on nutrition and benefits s of mushroom consumption could induce consumers to buy brown button mushrooms.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.491-498
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• 2011

We investigated the ranges of total cellular microcystins content of cyanobacterial blooms collected in Korean lakes and rivers from 2005 to 2009. The amount and composition of microcystins of Korean cyanobacteria varied depending on the sampling water bodies and dominant cyanobacterial genera. Toxic cyanobacterial cell numbers equivalent to $1{\mu}g$ MCYSTs/L using total cellular microcystin content of Korean cyanobacteria were in the range of 2,348 to 66,980,638 cells/mL. Only four samples among forty nine samples showed less cell numbers than current criterion of Harmful Algae Alert System, 5,000 cells/mL indicating current criterion do not reflect properly the microcystins content of Korean cyanobacteria. Anabaena and Aphanizomenon spp. showed three to six times higher cell numbers equivalent to $1{\mu}g$ MCYSTs/L than Microcystis spp. To propose criteria of Harmful Algae Alert System for Korean toxic cyanobacteria, we calculated about 50% selective geometrical means of cyanobacterial cell numbers equivalent to $1{\mu}g$ MCYSTs/L in order of toxic content. The proposed criteria for Microcystis, Oscillatoria, Anabaena, and Aphanizomenon spp., are 10,000, 20,000, 40,000, and 80,000 cells/mL, respectively.

• 한국체육학회지인문사회과학편
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• v.57 no.1
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• pp.347-367
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• 2018

The purpose of this study is to explore the meaning of YangSaeng exercise as a recreational activity for older adults. Twelve older adults who participated in the 'YangSaeng Exercise' at the S Senior Welfare Service Center were interviewed through purposeful sampling method. Each participant was interviewed two times, and data were analyzed using Strauss and Corbin's(1988) grounded theory method. Centralization was appeared as 'An addiction to YangSaeng exercise' and causal conditions were appeared as 'Visiting Welfare Center' and 'Participation in YangSaeng exercise program' and situational context were appeared as 'Self-management of old ages' and 'For possession of Independent Life' as the results of Axial Coding. Moreover, arbitrational conditions were 'Coexistence of Regret and Attraction' and interaction strategies were appeared as 'Accept', 'Effort and Easing Mind' and 'Share Together'. As a result, 'Appreciation', 'YangSaeng Exercise that comes in my Life' and 'Softly Pitapat' were derived. Core category of 'Living Joyfully with comforted and eased' was selected through outline of story which means it contains Positivity and Expectations, Acceptance and Acknowledgement, Satisfaction and Appreciation, and Commitment and Hope. Based on the findings, we acknowledge that YangSaeng exercise plays a role in improving quality of life of older adults as a recreational activity. This study sheds light on the possibility of implementing 'YangSaeng Exercise' as a health promotion activity among older adults.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.705-715
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• 2016

The purpose of this research is to analyze elementary students' attention characteristics through attention test and eye tracking on real science classes. The SMI's ETG(eye tracker glasses) mobile eye tracker was used to analyze the attention process of elementary students'. The sampling rate of the ETG is 30Hz. The participants of attention test were elementary 155 6th-grade elementary students and the participants for the eye-tracker were six 6th-grade male students. The eye movements were analyzed using the 'BeGaze Mobile Video Analysis Package' program. The results of this research are as follows. First, the attention test results of elementary students showed high correlation between selective attention and sustained attention (.85) and low correlation between selective attention and self-regulation (.32). Second, the attention types of elementary students were divided into four; attention, inattention, easygoing and hasty. Third, elementary students' attention were divided into top-down, bottom-up, default mode network through analysis of elementary students′ eye-movements during real science classes. Also their attention shift occurred frequently due to various reasons in real class situation. There were three reasons that made elementary students fail to handle knowledge-dependent top-down attention; 1) the cognitive failure of target caused by failing to focus attention, 2) the absence of prior knowledge on target object, 3) the analogical failure of prior knowledge. Finally, elementary students' attention process were schematized based on the analysis of students' eye movements and attention test. This research is expected to be utilized as basic data for developing effective teaching strategies, teaching-learning models and instructional materials.