• 제목/요약/키워드: Primary and Secondary School

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Analysis and Design of Transformer Windings Schemes in Multiple-Output Flyback Auxiliary Power Supplies with High-Input Voltage

  • Meng, Xianzeng;Li, Chunyan;Meng, Tao;An, Yanhua
    • Journal of Power Electronics
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    • v.19 no.5
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    • pp.1122-1132
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    • 2019
  • In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

Investigating Teachers' Perception of the Educational Resource Sharing System in Korea: A Qualitative Research

  • Sewon JOO;Innwoo PARK
    • Educational Technology International
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    • v.24 no.2
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    • pp.115-141
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    • 2023
  • The aim of this research is to understand the perceptions of primary and secondary teachers regarding educational resource sharing systems(ERS) by using a qualitative approach. This study conducted Focus Group Interview(FGI) with 20 primary and secondary school teachers. Interview data were analyzed through inductive content analysis method. The results are as follows. First, teachers placed significant emphasis on high-quality, convenient functions, and reward system for sharing resources. Specifically, teachers identified the necessity for a diverse array of materials, systematic categorization of these resources, and the provision of monetary compensation as essential components. Second, the study participants advocated strategies for revitalizing ERS including enhancing accessibility, constructing user-friendly features, increasing awareness, and establishing a reward system to incentivize the resource sharing. In particular, teachers proposed strategies such as developing mobile-based services and AIdriven data recommendation system. These results provide actionable insights for stakeholders engaged in the design, implementation, and evaluation of resource sharing platforms.

Abnormal Sound from Heat Exchanger of Condensate Water System at Nuclear Power Plant (원전 복수계통 열교환기의 이음 원인 분석)

  • Lee, Jun-Shin;Lee, Wook-Ryun;Kim, Tae-Ryong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.4
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    • pp.469-474
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    • 2016
  • Abnormal sound was heard from a heat exchanger of condensate water system in a nuclear power plant, which was identified as impact sound of a loose part later. Nuclear power plants are normally equipped with loose part monitoring system for primary water system, but not for secondary water system. The abnormal sound was analyzed by using the impact signal-processing methodology based on the Hertz theory. The predicted results for impact location and size of the loose part showed good agreement with those of the actual loose part found during the overhaul period in the plant. So, this analysis methodology for the impact signal will be widely utilized for the primary and secondary side of the nuclear power plant.

Soft Combination Schemes for Cooperative Spectrum Sensing in Cognitive Radio Networks

  • Shen, Bin;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.31 no.3
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    • pp.263-270
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    • 2009
  • This paper investigates linear soft combination schemes for cooperative spectrum sensing in cognitive radio networks. We propose two weight-setting strategies under different basic optimality criteria to improve the overall sensing performance in the network. The corresponding optimal weights are derived, which are determined by the noise power levels and the received primary user signal energies of multiple cooperative secondary users in the network. However, to obtain the instantaneous measurement of these noise power levels and primary user signal energies with high accuracy is extremely challenging. It can even be infeasible in practical implementations under a low signal-to-noise ratio regime. We therefore propose reference data matrices to scavenge the indispensable information of primary user signal energies and noise power levels for setting the proposed combining weights adaptively by keeping records of the most recent spectrum observations. Analyses and simulation results demonstrate that the proposed linear soft combination schemes outperform the conventional maximal ratio combination and equal gain combination schemes and yield significant performance improvements in spectrum sensing.

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Chest wall tumors [131 cases] (흉벽종양)

  • Jo, Gyu-Seok;Park, Ju-Cheol;Yu, Se-Yeong
    • Journal of Chest Surgery
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    • v.17 no.3
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    • pp.516-521
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    • 1984
  • We have experienced 131 cases of chest wall tumor, from April 1974 to April 1984 at the Kyung Hee University hospital. We analyzed 131 cases of chest wall tumors, 59 cases were primary chest wall tumors and 72 cases were secondary chest wall tumors. The results were following; 1.Of primary benign chest wall tumors [56], lipomas were most common and located mainly in the scapular area [37/56]. 2.Of secondary malignant chest wall tumors [72], which originated from hung tumors were most common [27/72], & breast [8/72], liver [8/72], prostate [6/72] & stomach [3/72] were followed lowed in orders. 3.We excluded out the Rib tuberculosis.

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A study on Engineering Professionals' Recognition about Engineering Education in Primary and Secondary School (초.중등교육에서의 공학교육에 대한 공학전문가들의 인식 연구)

  • Kim, Ki-Soo;Kim, Young-Min;Huh, Hye-Yeon;Lee, Chang-Hoon
    • 대한공업교육학회지
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    • v.38 no.2
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    • pp.136-155
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    • 2013
  • The purpose of this study is to analysis the recognition of engineering professionals in Primary and middle school education. For the study, survey was proceeded through experts in engineering. The result of research follows. First, experts in engineering recognized that engineering has a significant impact in the national economic development and competitiveness. Experts in engineering, had a recognition consistent to some extent for engineering. and we have found engineering's own characteristics that emphasize "problem solving and design, innovation and creativity, economy optimization". Second, experts in engineering recognized that engineering education in Primary and middle school rarely take place, and also does not provide enough information for students. Third, experts in engineering recognized that engineering education is very needed in Primary and middle school. Through this, students can understand creative design problem-solving process. In addition, Experts of engineering, have a variety of educational demands for School level to the level of engineering education should start, level educational purposes, how to apply effective and so on.

Bacterial Removal Efficiencies by Unit Processes in a Sewage Treatment Plant using Activated Sludge Process (활성슬러지공정 하수종말처리장의 단위공정별 세균 제거효율)

  • Lee, Dong-Geun;Jung, Mira;Sung, Gi Moon;Park, Seong Joo
    • Journal of Korean Society on Water Environment
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    • v.26 no.5
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    • pp.871-879
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    • 2010
  • To figure out the removal efficiency of indicator and pathogenic bacteria by unit processes of a sewage treatment plant using activated sludge process, analyses were done for incoming sewage, influent and effluent of primary clarifier, aeration tank, secondary clarifier and final discharge conduit of the plant. A matrix of bacterial items (average of bacterial reduction [log/ml], p value of paired t-test, number of decreased cases of twenty analyses, removal percentage only for decreased cases) between incoming sewage and final effluent of the plant were heterotrophic plate counts (1.54, 0.000, 20, 95.01), total coliforms (1.38, 0.000, 19, 83.94), fecal coliforms (0.90, 0.000, 20, 94.84), fecal streptococci (0.90, 0.000, 20, 98.08), presumptive Salmonella (0.23, 0.561, 7, 99.09), and presumptive Shigella (1.02, 0.002, 15, 92.98). Total coliforms, fecal coliforms, heterotrophic plate counts, and fecal streptococci showed highest decrease through secondary clarifier about 1-log (p<0.001) between 88% and 96%, and primary clarifier represented the significant (p<0.05) decrease. However, final effluent through discharge conduit showed higher total coliforms and fecal streptococci than effluent of secondary clarifier (p<0.05). In addition, final effluent once violated the water quality standard while effluent of secondary clarifier satisfied the standard. Hence some control measures including elimination of deposits in discharge conduit or disinfection of final effluent are necessary.

Multihop Transmission in Cognitive Underlay Network Over Rayleigh Fading Channels (레일리 페이딩 채널에서 이상 인지 언더레이 네트워크 멀티 홉 전송)

  • Park, Sang-Young;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.6
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    • pp.291-296
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    • 2012
  • In this Paper, we propose a multi-hop transmission in cognitive underlay network. In Secondary network, We assume that a secondary source S attempts to transmit D its signal to a secondary destination via N+1 hops with help of N relays $R_1$, $R_2$, ${\ldots}$, $R_N$. At hop k between relay $R_k$ and relay $R_{k+1}$. we assume that there is a primary user $PU_k$. In this paper, we assume that these channels are Rayleigh fading channels. In underlay network, the secondary transmitter has to adapt its power so that the interference caused at the primary user is less than a maximum interference threshold. considering the hop transmission between the transmitter and the repeater, we find transmit power and signal-to-noise ratio(SNR). Between the transmitter from the receiver depending on the number of relay in the underlay network, we compared to find the transmit power and signal-to-noise ratio(SNR). Finally we find optimal number of relay and optimal threshold value.

The Spatio-temporal Changes in the Sphere Influence of the Secondary Education in Geochang-Gun, Gyeongnam (거창군 중등교육세력권의 시.공간적 변화)

  • Lee, Jeon;Park, Woo-Sang;Lee, Jong-Ho
    • Journal of the Korean association of regional geographers
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    • v.12 no.6
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    • pp.656-670
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    • 2006
  • In Gcochang-Gun, the population decrease, due to a rural exodus phenomenon, has led to the absolute decline in the numbers of both primary and secondary schools and students. However, the high schools in Geochang-Gun show an unusual characteristic that the students from other areas outside Geochang-Gun cover about 25% of the total students studying in Geochang-Gun. This is quite contrary to the contention that one of the major factors hindering the development of rural areas is generally the inferior condition of education. In this context, this paper aims to explore the spatio-temporal changes in the sphere of influence of the secondary education with special reference to Geochang-Gun, Gyeongnam. Most importantly Geochang High School and Geochang Daesung High School account for over 98% of the students coming from other areas outside Geochang-Gun's cross-border counties. This means that the sphere of influence of the Geochang's secondary education is dependent largely upon the two private academic high schools.

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Manifest Weeds and Self-Actualization of Patients with Essential Hypertension (본태성 고혈압 환자의 자기실현 및 욕구구조에 관한 연구)

  • 강익화
    • Journal of Korean Academy of Nursing
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    • v.8 no.1
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    • pp.163-180
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    • 1978
  • Much of a person's energy is spent in the effort of becoming a productive member of to-day's complex society. This activity may cause tension, and chronic unrelieved tension is an influential factor in blood pressure elevation. The problem of this study was to identify manifest needs and self-actualization of patients with essential hypertension, and to analyse and compare their manifest needs and selt-actualization with the selected general characteristics of We, sex, religion, occupation and level of education with a control group of patients with normal blood pressure readings. The purpose was to contribute to the planning of nursing interventions toward reducing the impact of complex psycho-somatic factors on the anxiety of patients with essential hypertension. The instruments used included selected items from the Edwards (1959) Personal Preference Schedule (EPPS) as adapted by Hwang (1965) and from the Personal Orientation Inventory (POI) (Shostrom 1964, 1974) adapted by Kim and Lee (1977) to measure manifest needs and self-actualization. The convenience sample was chosen from 149 persons who presented themselves for general physical examinations at Ewha University Medical Centre and 41 patients diagnosed with essential hypertension at three general hospitals in Seoul during June 1 and August 31, 1977. Forty-nine persons from the Ewha group with blood-pressure readings exceeding 150/90 were added to the experimental group. Data were analysed by the S.P.S.S. computer programme using t-test and tests for statistical significance. Statistically significant findings were as follows: A. Blood Pressure and Manifest Needs. 1. with the exception of Autonomy, patients with hypertension had significantly high scores on all variables Abasement, Achievement, Affiliation, Aggression, Dominance, Emotionality, Exhibitionism and Sex. 2. When mean scores of normal persons were compared by age groups, normal persons had higher scores in the following order on Abasement (50's, 40's, 20's, 30's), Achievement (50's, 30's, 40's, 20's), Affiliation (50's, 40's, 30's, 20's), Dominance (50's, 40's, 40's, 20's) and Exhibitionism (30's, 50's, 40's, 20's). In each case, there was a significant difference between the first and last age group scores. 3. When the mean scores of normal persons were compared by sex, normal men had higher scores than women on Achievement, Affiliation, Aggression, Dominance, Exhibitionism and Sex. Male patients had higher scores than female patients on Achievement, Dominance, Exhibitionism and Sex, but female patients scored higher in Emotionality. 4. Normal persons had higher scores related to religion in the following order on Achievement (Buddhism, no religion, Christianity). Hyper tensive patients had higher scores on. Exhibitionism (no religion, Christianity, Buddhism). 5. Normal persons had higher scores related to occupation in the following order on Achievement and Exhibitionism (unemployed, office workers, teachless, businessmen), Emotionality (office workers, unemployed, businessmen, teacher) and Sex (office workers, unemployed, teachers, businessmen). Hypertensive patients had higher scores on Achievement and Aggression (teachers, businessmen, office worker, unemployed), Dominance and Exhibitionism (businessmen, teacher, of ace workers, unemployed) and Sex (teachers, office worker, businessmen, unemployed). 6. Normal persons had higher scores related to level of edification in the following order on Abasement, Emotionality and Autonomy (secondary school graduation, university). Hypertensive patients had higher scores on Abasement (no education, primary, university, secondary), Achievement (no education, secondary, university, primary) , Dominance (university, no education, secondary, primary), Exhibitionism (university, secondary, no education, primary), and Sex (university, secondary, primary, no education). B. Blood Pressure and Self_Actualization 1, Patients with hypertension had significantly lower scores on all variables. 2. Normal persons had higher scores related to age groups in the following order on Existentiality (20's, 30's, 40's, 50's). Hypertensive patients showed no significantly different scores. 3. Normal women had higher scores than men on Time Competence. Normal men had higher scores on Feeling Reactivity. Male patients had higher scores than women on Self-Actualizing Value and Self-Regard. 4. Normal persons ha 1 higher scores related to religion on spontaneity (Buddhism, no religion, Christianity). Hypertensive patients had higher scores on Time Competence and Nature of Man (Buddhism, Christianity, no religion). 5. Normal persons had higher scores related to occupation in the following order on Existentiality (teachers, office workers, businessmen, unemployed) and Self-Regard (unemployed, office workers, teachers, businessmen). Hypertensive patients showed no significantly different scores. 6. Normal persons had higher scores related to level of education in the following order on Existentiality and Self-Acceptance (university, secondary). Hypertensive patients had higher scores on inner-Director (university, secondary, no education, primary) and Existentiality (university, secondary, primary, no education). Recommendations for nursing interventions with hypertensive patients with emotional problems or low self-actualization were made. 1. The nurse should encourage the patient through her interactions with other members of the medical team to accept counselling and health education. 2. Through her therapeutic interpersonal relationships with the patient, the nurse should help him discover the causes of his emotional tension. 3. Through her health teaching with the family, the nurse should encourage them to participate with the medical team in the patient's therapeutic plan and in providing him with the minimum possible emotional support. 4. Through frequent counselling with the obsessive-thinking and inflexible patient, the nurse should reevaluate the patient's behaviour and her interventions. 5. Seriously ill patients should be given needed reeducation by members of the professional medical team.

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