• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.799-805
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• 2016

Objectives: The purpose of this study was to know instructors' needs of integrated curriculum in dental hygiene practice.. Methods: A self-reported questionnaire was completed by 112 instructors in Korea from June to July, 2015. The statistical analyses include frequency, percentage and Mann-Whitney' U test using SPSS 12.0 program. The questionnaire comprised needs of curriculum(5 items), integrated curriculum(10 items). Results: Need of integrated curriculum in practice course was statistically significant in school system(p=0.048) and number of students(p=0.041). The enhancement of clinical competence was high in teaching experience($11{\leq}$)(p=0.009) and perceptions of problems was high in experience of teaching($10{\geq}$)(p=0.047). In integrated curriculum, enhancement of clinical competence was statistically significant in school system(p=0.035) and number of students(p=0.011). Increase of professionalism was high in University(p=0.021), number of students(p=0.006) and teaching experience($10{\geq}$)(p=0.062). Conclusions: In order to improve curriculum in each institutions, it is necessary to measure in the view of representative institutions dimensions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.128-136
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• 2006

In this paper, design and implement 50W Doherty power amplifiers for 3GPP repeater and base station transceiver system. Efficiency improvement and high power property of ideal Doherty power amplifier is distinguishable; however bias control for implementation of Doherty(GDCHD) amplifier is difficult. To solve the problem, therefore, GDCHD(Gate and Drain Control Hybrid Doherty) power amplifier is embodied to drain bias adjustment circuit to Doherty power amplifier with gate bias adjustment circuit. Experiment result shows that $2.11{\sim}2.17\;GHz$, 3GPP operating frequency band, with 57.03 dB gain, PEP output is 50.30 dBm, W-CDMA average power is 47.01 dBm, and -40.45 dBc ACLR characteristic in 5MHz offset frequency band. Each of the parameter satisfied amplifier specification which we want to design. Especially, GDCHD power amplifier shows proper efficiency performance improvement in uniformity ACLR than Doherty power amplifier.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.157-163
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• 2018

This paper describes design improvement to a research rector for safety enhancement using Probabilistic Safety Assessment (PSA). This PSA under reactor design was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA reported here is a Level 1 PSA, which addresses the risks associated with the core damage. The technical objectives of this study were to identify accident sequences leading to core damage and to derive design improvement from the dominant accident sequences through the sensitivity analysis. The AIMS-PSA and FTREX were used for the this PSA of the research reactor. The criterion for inclusion was all sequences with a point estimate frequency greater than a truncation value of 1.0E-14/yr. The final result indicates a point estimate of 6.79E-05/yr for the overall Core Damage Frequency (CDF) attributable to internal initiating events for the research reactor under design. Based on the dominant accident sequences from the PSA, the seven kinds of sensitivity analysis were performed and some design improvement items were derived. When the five methods to improve the safety were all applied to the reactor design and emergency operating procedure, its risk was reduced to about 1.21E-06/yr from 6.79E-05/yr. The contribution of LOCA and LOEP with high CDF were significantly reduced by the sensitivity analysis. The safety of the research reactor was well improved and the risk was reduced than before adapting the design improvement gotten from the sensitivity analysis. The present study indicated that the research reactor has the well-balanced safety in regard to each initiating event contribution to CDF. The PSA methodology is very effective to improve reactor safety in a conceptual design phase and especially, Risk-informed design(RID) is very nice way to find the deficiencies of research reactor under design and to improve the reactor safety by solving them.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.127-137
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• 2000

This study presents an analysis of the characteristics of vertical ozone distribution near the surface using ozonesonde data(l995 to 1998), plus surface ozone and meteorological data from the Pohang region. These features were examined in detail using three case studies. The first related to episodes of high surface ozone concentrations during the Spring season when the frontogenesis between the high and low pressure associated with the upper-level jet stream was found to be located near the surface. The second was a 5-day winter period(l3 -17 December, 1997) in the Pohang province when the hourly concentrations exceeded 90 ppb on several occasions owing to low-level jets(LLJs) induced by a nocturnal stable layer. Accordingly, this explains why the high surface ozone concentrations occurred at night as the ozone was transported across the zone by a strong wind speed( over 12.5 ms .1). The third case study was ozone enhancement due to photochemical reactions. In this case, the maximum concentration of ozone exceeded 60 ppb in the summer(23 -28 August, 1997). When an ozone peak appeared within the boundary layer, the occurrence frequency of a low-level jet due to the nocturnal stable layer was about 77%, similarly the occurrence frequency of a near-surface ozone peak relative to the appearance of an LLJ was about 76%. Accordingly, there is clearly a close correlation between the occurrence of LLJs and near-surface ozone peaks.

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.371-380
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• 2011

The noise caused by a variety of reasons worsens the quality of input image when we use the images reproducing device. The basic difficulty to solve this problem is that the noise and the signal are difficult to be distinguished. Contrast enhancement such as unsharp masking is one of the most important procedures to improve the quality of input images. The conventional unsharp masking enhances the images by adding their amplified high frequency components. The noise component of the input images, however, also tends to be amplified due to the nature of the unsharp masking. This paper considers the block approach for detecting niose and image feature of the input image so that the unsharp masking could be adaptively applied accordingly. Simulation results show that it is made possible to enhance contrast of the image without boosting up the noisy components by applying the proposed algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.56-63
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• 2012

In this paper, adaptive unsharp masking using bilateral filter, edge-preserving smoothing filter is proposed to reduce the overshoot and jagging artifact in sharpening images. Previous image enhancement methods including unsharp masking(UM) can emphasize high-frequency details strongly, but often cause several artifacts such as overshooting, noise, jagging and so on. Proposed image enhancement method preserves edges well because of using bilateral filter and sensitively controls a weight according to edge's directions. Therefore, it enhances sharpness and effectively reduces overshoot and jagging artifacts. Simulation results comparing output of previous AUM with proposed method show that proposed algorithm makes images properly enhanced, and we know that overshoot and jagging artifacts are many reduced.

• Journal of Korean Home Economics Education Association
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• v.10 no.2
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• pp.131-144
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• 1998

The lack of characteristical understanding of the Home Economics Education will have difficulty in achieving the goal of the Home Economics Education. To allow the Home Economics Education class in school contribute toward the enhancement of the quality of life, it is inevitable to reinforce the recognition of the importance and necessity of the Home Economics Education and to newly propose a directional guidance forward the coming 21st century. The purpose of this study was to provide basic data for planners of the future Home Economics Education by surveying research administrators in charge of programming the overall school curriculum. This study was conducted under the following procedure to have the outcome as follows ; 1. Answers from respondents of age over 50 or careers over 16 years tended to grasp the goal of Home Economics Education in relation to the enhancement of quality of life rather than to the accumulation of knowledge, skill or capacity. 2. Of all the surveyed, 9.64% regarded Home Economics Education as an essential part of school education and the positive ratio was higher with younger respondents. 3. To the question asking if the high school Home Economics Education could have influence on one's capacity, 97.2% of the answerers said yes. The respondents with career under 15 year showed 100% of positive agreement in this matter and of age under 40 marked much higher ratio of 98.84% than the elders. 4. The overall recognition of the necessity for separate sections in Home Economics Education programmed in accordance with the 6th Revision of High School Curriculum displayed a considerably high ratio, with a little differences among age and job groups. The purpose of this study is to analyze and understand adolescents'culture, thereby to provide fundamental information for Preventive Education for Adolescents'Problems in Home Economic Education. 745 articles collected in computer communication service were used for the analysis. The data were analyzed by frequency and percentage using the SPSS/PC+computer program. The most important results of this study were as follows ; 1) Concerning 'Adolescent's Problems's, problems such as violence, homicide and robbery were treated with the greatest frequency. It was also analyzed that the older generations are highly inclined to understand adolescents'culture as a negative one, for example, 'delinquency'or 'immaturity'. 2) Although the area of 'Adolescents'Education'was treated most frequently reflecting the high educational concern in our society, the significant part of those articles were on wrongful educational administration. As much as 70.6% of the articles analyzed were on 'Education'and 'Problems'. Thereby it may be concluded that the other areas such as health, activities, worries, values and harmful environments ere treated respectively as only a 'subculture'or'fragmentary culture'. The articles containing correlations and interactions among them and certain alternative proposals were very rare. 3) The areas such as 'Worries and Counselling'and 'Health'were occupying only a small portion of the articles. The articles which were treating the practical worries and their resolutions were even rarer. 4) 'Values'of the adolescents tended to be viewed by the older generations very negatively. It was also found that the older generations gave the tendency to see the 'consumption culture'of the adolescents as a kind of 'counter culture'or'subculture'.

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.148-154
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• 2009

In audio coding, SBR technology synthesizes the high-bands using patched time-frequency information from low-bands and the correction parameters, Since SBR transmits only correction parameters for high-bands, it provides a low-rate coding of high-bands, and is used as a core module of MPEG-4 HE-AAC, SBR was originally designed for audio signal and its performance for speech signal tends to decrease, and the major reason is an excessive noise floor in high-bands which is caused by incorrect tonality computation, In this paper, a new method to determine noise floor level in an adaptive fashion according to the speech characteristics is proposed in order to solve the problem of SBR for speech signal, The proposed method maintains the compatibility with the standard SBR, and the subjective performance evaluation shows that the proposed method improves the SBR performance especially for male speech signal compared with the standard SBR.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.869-872
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• 2008

This paper presents the VHDL implementation procedure of the passive RFID tag in Ultra High Frequency RFID system. The operation of the tag compatible with the EPCglobal Class1 Generation2(GEN2) protocol is verified by timing simulation after synthesis and implementation on prototyping board. Due to the reading range with relatively large distance, a passive tag needs digital processor which facilitates faster decoding, encoding and state transition for enhancement of the interrogation rate. Also with UART communication, verify a inventory Round in Gen2 Protocol. The verification results with the fastest data rate, 640kbps, and multi tags environment scenario show that the implemented tag spend 1.4ms transmitting the 96bits EPC to reader.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1749-1753
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• 2003

We proposed several systems for 1Giga bit Modem. The first, Binary ASK(Amplitude Shift Keying) system has a high speed shutter transmitter and no IF(Intermediate Frequency) receiver only by symbol synchronization. The advantage of proposed system is that circuitry is very simple without IF process. The disadvantage of proposed system are that line spectrum occurs interference to other channels, and enhancement to 4-level system is impossible due to its large SNR degradation. The second, Binary phase modulation system has a high speed shutter transmitter and IF-VCO(IF-Voltage Controlled Oscillator) control by base-band phase rotation. Polarity of shutter window is changed by the binary data. The window should be narrow same as above ASK. The advantage of proposed system is which error rate performance is superior. The disadvantage of proposed system are that Circuitry is more complex, narrow pull-in range of receiver caused by VCO and spectrum divergence by the non-linear amplifier. The third, 4-QAM(Quadrature Amplitude Modulation)system has a nyquist pulse transmitter and IF-VCO control by symbol clock. The advantage of proposed system are that signal frequency band is a half of 1GHz, reliable pull-in of VCO and possibility of double speed transmission(2Gbps) by keeping 1GHz frequency-band. The disadvantage of proposed system are that circuit complexity of pulse shaping and spectrum divergence by the non-linear amplifier.