• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.77-81
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• 2001

This paper proposed a novel chip type ceramic dielectric antenna by using the advanced meander line technique that the radiational metals are formed on the face of ceramic dielectric(8 ${\times}$ 4 ${\times}$ 1.5 mm, alumina) and both facses of substrate(1.0 mm thickness, FR-4). The performance of the antenna model has a good agreements between measurements and computed results. Resultly, it has a 10 dB return-loss bandwidth(2.4～2.4835 GHz) and 1.7 dBi measured radiation gain for Bluetooth application. The proposed antenna model can overcome the problems of the radiation gain from the small antenna's size.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.183-186
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• 2004

Unipoled piezoelectric transformers were designed with different input and output area ratios. The voltage step-up ratio increased proportionally with increasing the input area. The piezoelectric transformers operated in each transformer's resonance vibration mode. In this paper, ANSYS(FEM program) was used for analysing piezoelectric transformers. We compared with analysis and experimental results. The voltage step-up ratio showed maximum value in output area of small size. Output characteristics of piezoelectric transformers with various size were simulated. The result of analysis showed 2~7 times higher voltage step-up ratio than a experiment result.

• Steel and Composite Structures
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• 제28권3호
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• pp.381-388
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• 2018

In this paper, forced vibration of micro cylindrical shell reinforced by functionally graded carbon nanotubes (FG-CNTs) is presented. The structure is subjected to transverse harmonic load and modeled by beam model. The size effects are considered based on strain gradient theory containing three small scale parameters. The mixture rule is used for obtaining the effective material properties of the structure. Based on sinusoidal shear deformation theory of beam, energy method and Hamilton's principle, the motion equations are derived. Applying differential quadrature method (DQM) and Newmark method, the frequency curves of the structure are plotted. The effect of different parameters including, CNTs volume percent and distribution type, boundary conditions, size effect and length to thickness ratio on the frequency curves of the structure is studied. Numerical results indicate that the dynamic deflection of the FGX-CNT-reinforced cylindrical is lower with respect to other type of CNT distribution.

• 한국인지과학회:학술대회논문집
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• 한국인지과학회 2000년도 춘계 학술대회
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• pp.247-251
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• 2000

This study examined relative importance of these factors by asking people to read the texts that was constituted with square and non-squre form letter and rank the preference of texts through conjoint analysis. In the case of reading time, font type was the most important factor, followed by leading , line width, font size, line length, justification, letter width in their order of impotance. And in the case of preference decision, font size was the most important factor, followed by font type, leading, line width, letter width, justification, line length. The result will be useful in understanding how to consider human preference in the Hangul typography.

• 한국IT서비스학회지
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• 제13권3호
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• pp.257-274
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• 2014

Social Network Services (SNSs) have grown to be new and promising tools of marketing. By referring to researches done on e-mail viral marketing, this paper operationizes SNS viral marketing effectiveness to accurately reflect marketing success in SNS environment, and tries to identify its affecting factors. As potential affecting factors, fan size, advertisement type, existence of engagement elicitation and incentive are identified. By sampling real advertisement postings on Facebook, we showed that fan size, advertisement type, and engagement elicitation are factors affecting SNS viral marketing success. This research expanded the conventional model of viral marketing into SNS settings to improve understanding on SNS viral marketing. Motivation is discussed as an important factor, and this research showed that viral campaign can be more successful when it triggers internal motivation to engage, but not the external motivation. This research could also be a guide for practitioners on how to post a successful advertisement in SNSs.

• 한국작물학회지
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• 제42권3호
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• pp.333-337
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• 1997

땅콩의 육종년한을 단축하기 위한 세대촉진 방법을 정립하고자 포장후건에서 신대광땅콩 및 남대땅콩을 재배하고, 자방병이 지하로 침투한 후부터 80일까지 10일 간격으로 꼬투리와 종실을 재취하여 그 크기와 무게, 수분함량의 변화를 추적하는 동시에 종실의 발아율과 발아한 유묘의 활력을 조사한 결과, 자방병이 지하로 침투한 후 30∼40일에 꼬투리와 종실의 크기가 완성되었고, 이 때에 수확한 종실은 100％ 발아력을 갖추며 발아 후 활력있는 유묘를 생산할 수 있는 것으로 나타났다.

• Journal of Biosystems Engineering
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• 제11권2호
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• pp.66-75
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• 1986

In order to improve the traditional post harvest system in Korea, a model for mechanized grain drying and storage facilities was developed. Also, a computer program for the model system was developed. For the study, flat type steel bin and circulation type dryer were selected for the model and Fortran language was used for the computer program. This program was tested by using various practical data. The following results were obtained from the study: 1. The general model developed can be used for designing a rough rice drying and storage facility within the range from 100 ton to 1000 ton capacity. 2. Major output of the computer program for designing a model system were as follow; a. The dimension of the plant. b. The storage bin size, dryer number and dryer size. c. The dimension of individual equipment and its required HP. d. Capital requirement and operating cost of the model system.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권5호
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• pp.196-203
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• 2005

A semi-empirical method to determine the electrostatic characteristics of a diode type corona aerosol charger based on ion current measurement and electrostatic charging theory was presented. Results from mathematical model were in agreement with those from experimental investigation of the charger. Current-voltage characteristics, $N_{i}t$ product and charge distribution against aerosol size were obtained. It was shown that the space charge was significant and must be taken into account at high ion number concentration and low flow rate. Additionally, significant particle loss was evident for particles smaller than 20 nm in diameter where their electrical mobility was high. Increase in charging efficiency may be achieved by introducing surrounding sheath flow and applying AC high voltage. Overall, the approach was found to be useful in characterizing the aerosol charger.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.161-166
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• 2005

The objectives of this paper are to estimate the ground thermal conductivity by ground heat exchangers in two different places - Chooncheon and Wonjoo, and to analyze the effect of ground thermal conductivity on the ground thermal diffusivity and the size of the ground heat exchanger. In Chooncheon area, a single-U type HDPE pipe (25mm diameter) with borehole diameter of 150mm, length of 150m is installed. In Wonjoo area, a single-U type HDPE pipe (40mm diameter) with borehole diameter 150mm, length of 200m is installed. It is found that the ground thermal conductivities are estimated as 2.69 $W/m^{\circ}C$ and 2.99 $W/m^{\circ}C$ in Chooncheon and Wonjoo, respectively. It is also found that the ground heat exchanger size is reduced by 8.6% with 25% increase of ground thermal conductivity, and increase by 11.8% with 25% decrease of ground thermal conductivity.

• ETRI Journal
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• 제28권5호
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• pp.574-582
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• 2006

In this paper, a new error concealment algorithm is proposed for the H.264 standard. The algorithm consists of two processes. The first process uses a fuzzy logic method to select the size type of lost blocks. The motion vector of a lost block is calculated from the current frame, if the motion vectors of the neighboring blocks surrounding the lost block are discontinuous. Otherwise, the size type of the lost block can be determined from the preceding frame. The second process is an error concealment algorithm via a proposed adapted multiple-reference-frames selection for finding the lost motion vector. The adapted multiple-reference-frames selection is based on the motion estimation analysis of H.264 coding so that the number of searched frames can be reduced. Therefore the most accurate mode of the lost block can be determined with much less computation time in the selection of the lost motion vector. Experimental results show that the proposed algorithm achieves from 0.5 to 4.52 dB improvement when compared to the method in VM 9.0.