• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.10 s.113
• /
• pp.1007-1019
• /
• 2006

In this paper, the synthesis method of multibeam radiation pattern with multi-directional beams and nulls is proposed. Genetic algorithm is applied for the optimization of amplitude and phase of the feeding signal into each element that is structured in planar array of single patch antenna with an arbitrary field distribution. To verify the validity of the proposed method, $2{\times}2$ planar array antenna is used for the measurement and the measured far field radiation pattern is compared with the simulation result. As a result, the synthesis of multibeam radiation pattern is implemented by the optimization of amplitude and phase of the feeding signal into each element of $8{\times}8$ planar array antenna system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.10
• /
• pp.1097-1106
• /
• 2009

In this paper, the cross monopole antenna with branch element is presented and its radiation characteristics are investigated. To confirm the broadband characteristics of the proposed antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in PCS, WCDMA, WiBro and S-DMB band(1.750~2.655 GHz). It is shown that the designed antenna has the non-directional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5 and gain over 1.9 dBi in 1.72~2.82 GHz. From these results, the presented antenna is conformed as a broadband antenna which can be used for PCS, WCDMA, WiBro and S-DMB band.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.8
• /
• pp.299-307
• /
• 2013

In this paper, design of UWB Antenna which propagate impulse by pulse fidelity and distortion equation was induced and applied. UWB Antenna which has directional characteristic in UWB band should have low radiation loss and impulse radiation distortion. As a result, the paper designed wide band impedance transformer and microstrip slotline transit region structured antenna feeder line. By using the fabricated UWB antenna, the radiation pattern was measured in the radio anechoic chamber. Pulse fidelity of impulse radiation show good results more than 93% within ${\pm}30^{\circ}$ beam width.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.31 no.9_10
• /
• pp.1373-1383
• /
• 2007

The purpose of this study is to find out the dimensions of kidult fashion emotion and identify the influence of socio-psychological characteristics(nostalgic orientation, change inclination, and self-esteem) on kidult fashion emotion. 'Kidult', composite of kid and adult is indicating a group of people who feel nostalgic for and feel attachment to the products that they have been used in their childhood. A questionnaire was prepared in the survey and a total of 474 women in their twenties and thirties who had purchased the kidult fashion products were selected. The research findings are as follows: 1. Kidult fashion emotion can be classified as 5 factors: pursuits of fashion emotion, seeking girlish image emotion, preference for character emotion, seeking fun emotion, and past oriented emotion. 2. Socio-psychological variable that affected kidult fashion emotion is turned out change inclination. 3. The higher the seeking girlish image and pursuit of fashion emotion tendencies, the more they purchase the kidult fashion products. Based on these results, kidult fashion emotions are not the attachment to the past but positive expression of self and individuality.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3608-3613
• /
• 2009

In this paper, we propose a mobile Radio Frequency Identification antenna for mobile hand set. The proposed antenna with directive radiation characteristics based on combination of electric-magnetic radiators can be installed in the mobile hand-set. The combination of PIFA antenna for electric radiator and loop antenna for magnetic radiator is presented and designed for료 m-RFID reader system. Target frequency band is 900-MHz band. and desired gain is 4dBi. The antenna is simulated using Ansoft HFSS software and shows expected results. The antenna is also manufactured using FR4-epoxy circuit board (h=1 mm, $\varepsilon_{\tau}=4.4$). There are good agreements between the simulated and measured VSWR curves and radiation characteristics.

• Journal of KSNVE
• /
• v.7 no.1
• /
• pp.71-79
• /
• 1997

The objective of this study is to investigate experimentally the effect of surface conditions of the plate on the impinging jet noise. The experimental results about the spectrum, the sound pressure level and the directivity are pressented and discussed in relation with the surface conditions. Regardless of the surface conditions, the pure tones of high level are generated at the same frequency band and the overall sound power level of impinging jets is much higher than that of the free jet. However, the velocity dependence of the sound pressure level and the directivity are different between smooth surfaces and rough surfaces. The dependence of sound pressure level on the jet velocity shows that the smooth surface generates quadrupole-type sound like free jets. However, the perforated or the rough surface radiates sound power exactly proportional to the sixth power of the jet velocity, indicating that the source is fixed dipole type. The directivities of 1/3 octave band sound pressure level for both the free and impinging jet show the peak directivity at 115$^\circ$ upstream, probably due to the refraction associated with velocity gradient.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.12
• /
• pp.4803-4811
• /
• 2010

As the role that information system and technique plays in hotel firms is critical, the quality of IS and IT is considered as one of most important factors that determine success of hotel firms. This study aims to examine the influences of the quality of IS/IT exerted on the user's level of acceptance of the HIS and the operational performance on both personal and organizational levels. Based on the data collected from 256 employees in reservation departments of 3 Seoul and 3 Busan deluxe hotels, the study tested the applied TAM model. The results indicated that the quality of IS/IT affects the user's acceptance level (eg., satisfaction and perceived usefulness), and such acceptance behavior affects reservation employees' performance on both personal and organizational levels. Managerial implications are also presented for researchers and practitioners of hotel firms.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.5 no.2
• /
• pp.83-89
• /
• 1996

The objective of this study is to find experimentally the characteristics of the noise generated by the impinging jet on the normal plate, and also to compare the noise characteristics of the impinging jet with those of the free jet. The experiment is performed for the measurement of the noise specturm, the noise power, and the directivity for the free and impinging jets. From the experiment. it is found that the power of noises generated by the free jet as well as the impinging jet is proportional to the eighth power of the jet velocity through the circular converging nozzle, and that the noise power of the impinging jet is 15dB as high as one of the free jet when the plate distance is about within one to three times the nozzle diameter at the pressure ratio 1.39. The sound pressure level of the impinging jet depends upon the jet pressure and the plate distance. The plate distance with the maximum overall sound pressure level is increased with the jet pressure. The directivities with 1/3 octave band frequency for both the free jet and the impinging jet are greatly influenced by the convection effect.

• Journal of Korean Society for Quality Management
• /
• v.37 no.3
• /
• pp.102-122
• /
• 2009

In this study, we will conduct an empirical study to see how the 3PL firm's logistics service quality and relationship orientation affects the supply chain performance. To examine the research model and hypotheses, we have used an empirical method based on the field survey in which most of measurements used and verified in previous studies are selected as measurements. The results of our empirical study can be summarized as follows: First, it can be shown that higher level of logistics service quality not only affects satisfaction and relationship orientation positively, but also improves supply chain performance. Second, it can be also shown that satisfaction for logistics service quality affects relationship orientation between shipper and 3PL firm positively. Finally, it can be shown that relationship orientation affects supply chain performance positively. This paper presents much implications both theoretical and practical side.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.1
• /
• pp.28-31
• /
• 2018

This paper investigates the ground reflection effect on the channel capacity of an orbital angular momentum (OAM) multi-mode transmission system that uses uniform circular array (UCA) antennas. The ground-reflected signals cause inter-mode interferences between the OAM modes, and lead to system performance degradation. The OAM multi-mode channel capacity severely degrades owing to the ground reflection as the transmission distance increases. Increasing the UCA height above the ground and using highly directive array elements can mitigate the ground reflection effect and increase the channel capacity.