• Title/Summary/Keyword: multi-frequency characteristics

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A CPW-Fed Self-Affine Cross Shape Fractal Antenna (자기 아파인 프랙탈 구조를 이용한 CPW 급전 크로스 안테나)

  • Kim Tae-Hwan;Lee Jae-Wook;Cho Choon-Sik;Lee Yun-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.9 s.100
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    • pp.949-956
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    • 2005
  • In this paper, a new CPW-fed cross shape fractal antenna having a self-affinity is presented. This novel configuration, which has anisotropic scaling symmetry, makes smaller profile characteristic compared to the fractal antenna using a self-similarity. Increase of the iteration coefficient, which leads to decrease of the fundamental resonant frequency, shows a good impedance matching condition and multi-band characteristics due to new surface current paths. The radiation patterns are similar to those of monopole antennas. In the K3 stage of iteration, the proposed antenna shows a measured maximum gain 2.27 dBi at 940 MHz. A commercially available software based on the FDTD algorithm has been used to obtain the predicted results. In addition, an RT/Duroid 5880 substrate has been employed for the experimental results.

Residents' Using Behaviors of Living Facilities According to the Developmental Concepts of Complexes - The Case of the 3 Complexes in Cheongju Area - (택지개발지구 특성에 따른 거주자의 생활권 내 근린시설 이용행태 - 청주권 3개 택지개발지구를 중심으로 -)

  • Lee, Sang-Un;Park, Kyoung-Ok
    • Journal of the Korean housing association
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    • v.21 no.5
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    • pp.13-22
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    • 2010
  • This study has the purpose to reveal the differences of residents' using behaviors of living facilities at 3 complexes. The physical characteristics of the complexes have been investigated by a literature study and field survey. In addition, questionnaires were answered by residents on living facilities using behavior on community environment. The tools of analysis are frequency, percentage, and cross tabulation using SPSS WIN 12.0 program. Followings are the results of the study. 1) The developmental concept of 3 complexes maintained its initial identity. (1) The residence-oriented complex, having wider residential space, had better downtown access and more convenient facilities for daily life. (2) The residence-government mixed complex, constructed with an eco-friendly concept, had wider green and public service space and good downtown access but on the other hand, had less convenience facilities because of a short period from construction. (3) The residence-industry mixed complex, located in sub-urbanity and conceding more land for industries, had poor access to downtown but had more convenient facilities for workers' use. 2) The most frequently visited convenience facilities were shopping facilities, large or small, and banks, and activities were commonly done in the complex or adjacent area. This means it is recommended that the developer of the new complex locate convenience facilities in multi-core concentration types or street types rather than one-core concentration types.

Nonlinear Dynamic Characteristics of Antisymmetric Laminated Shells (역대칭 적층쉘의 비선형 동적 특성에 관한 연구)

  • Park, Sung Jin;Mikami, Takashi;Kim, Young Jin
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.691-700
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    • 1998
  • Based on Von Karman-Donnell kinematic assumptions for laminated shells, the nonlinear vibration behaviour of antisymmetrically or asymmetrically laminated cross-ply circular cylindrical shells with clamped and simply-supported ends are studied by a multi-mode approach. A equation is formulated and satisfies the associated compatibility equation and all boundary conditions. The displacement function is assumed to take the form of the lowest linear vibration mode and to satisfy continuity of the circumferential displacement. The nonlinear vibration equation is derived by the Galerkin's method. And nonlinear frequency is obtained by using the harmonic balance method as a function of lamination parameters, material constants, aspect ratio and amplitude of vibration. The effect of initial imperfection is also included. Results of the non-linear vibration are presented for different amplitudes of initial imperfection and four sets of boundary conditions. Present results are compared well with existing analysis results.

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Compact Broad Band-pass Filter with SIR-Parallel Coupled Structure (SIR 평행결합 선로를 갖는 소형 광대역 대역통과 필터)

  • Hong, Tae-Ui;Lee, Jeong-Hun;Yoon, Ki-Cheol
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.11
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    • pp.84-90
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    • 2010
  • In this paper, the reduced size of broad bandpass filter with parallel coupled line structure is presented. This proposed filter can control bandwidth of narrow to broadband by adjusting the coupling coefficient. The conventional filter is operated with a narrow band. If a higher bandwidth is desired than the conventional narrow bandwidth, it is hard to realize due to the coupling coefficient between feeding line and resonator. In this paper, to overcome this limitation, a proposed bandpass filter is designed with reduced size due to SIR(Stepped Impedance Resonator) and multi-grade type structures than conventional one, and it has characteristics of adjusting bandwidth freely as per quantity of coupling coefficient. The proposed bandpass filter that, experimental results of insertion and return losses are 0.42 dB and 20.9 dB with bandwidth of 60 % at the center frequency of 5.8 GHz, respectively.

System Performance Analysis for Multi-Band SweepSAR Operating Mode (다중대역 SweepSAR 운용 모드의 시스템 성능 분석)

  • Yoon, Seong-Sik;Lee, Jae-Wook;Lee, Taek-kyung;Ryu, Sang-Burm;Lee, Hyeon-Cheol;Kang, Eun-Su;Lee, Sang-Gyu
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.3
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    • pp.186-194
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    • 2017
  • In this paper, we analyze the main performance of satellite's Synthetic Aperture Radar system for high resolution and wide swath. We have used the radiation pattern of reflector antenna with array feed and comparison between the conventional ScanSAR mode and SweepSAR mode has been carried out. The SweepSAR mode is a high-resolution wide-swath mode that transmits beams over a wide range and receives echo signals through sequential beamforming based on SCORE(SCan On REceive). In this paper, we analyzed the operating principle and characteristics of satellite's SweepSAR mode and simulate system performances. In addition, in order to increase the utilization of image, performances analysis for multiple frequency bands(C-band, X-band) has been considered.

Environmental Knowledge, Eco-Friendly Attitude and Purchase Intention about Eco-Friendly Fashion Products of Fashion Consumers (패션소비자의 환경지식, 친환경 태도가 친환경 패션제품 구매에 미치는 영향)

  • Park, Sung Hee;Oh, Kyung Wha
    • Fashion & Textile Research Journal
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    • v.16 no.1
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    • pp.91-100
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    • 2014
  • The purpose of this study was to examine the effect of consumer's environmental knowledge, eco-friendly attitude and purchase intention about fashion consumers' eco-friendly products. This study was conducted by a survey of 330 males and females fashion consumers in their 20s-40s who experienced eco-friendly fashion products purchase. Respondents, who had purchased eco-friendly fashion items at least once, were selected using convenience sampling through the online survey from March $20^{th}$ to $30^{th}$ in 2013. The collected materials were analyzed by frequency analysis, factor analysis, t-test and multi-regression using SPSS 19.0 software. Through the result of statistical analysis, it is found that environmental knowledge has three dimensions; natural environmental knowledge, urbanized environmental knowledge, environmental pollution knowledge. Also the effects of environmental knowledge on eco-friendly attitude are significant and eco-friendly attitude has influence on eco-friendly fashion products purchase behavior. Eco-friendly attitude had an effect word of mouth intention. In addition, there are notable differences in environmental knowledge, eco-friendly attitude and purchase intention depending on fashion consumer's age. The results of this study will provide useful information for both eco-friendly customer management and fashion marketing strategies. Therefore, the fashion company is needed to consider personal characteristics, customer needs and present condition of purchasing eco-friendly fashion products.

SPST Switch MMIC for Microwave Switch Matrix (마이크로웨이브 스위치 메트릭스 용 SPST 스위치 MMIC)

  • Chang Dong-Pil;Yom In-Bok;Oh Seung-Hyueb
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.2A
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    • pp.201-206
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    • 2006
  • A SPST Switch MMIC which used for Microwave Switch Matrix(MSM) of communications satellite payload with multi-beam function has been designed and fabricated. New RE FET switch configuration has been devised to improve power characteristics and isolation. Input and output return losses are better than another switches reported previously for both On and Off states. The MMIC chips were fabricated in 0.15um GaAs pHEMT process and measured insertion loss less than 2.0dB and isolation more than 63dB in the frequency range of 3GHz$\∼$4GHz. Output 3rd order interceptpoint above 32dBm has been recorded and the value is very high even though the unit pHEMT has gate width of 0.2mm and only four pHEMT are used in the MMTC.

Symptom Experiences and Coping Strategies among Multi-ethnic Solid Tumor Patients Undergoing Chemotherapy in Malaysia

  • Yahaya, Nor Aziyan;Subramanian, Pathmawathi;Bustam, Anita Zarina;Taib, Nur Aishah
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.2
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    • pp.723-730
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    • 2015
  • Background: This study was performed to assess patient symptoms prevalence, frequency and severity, as well as distress and coping strategies used, and to identify the relationships between coping strategies and psychological and physical symptoms distress and demographic data of cancer patients. This cross-sectional descriptive study involved a total of 268 cancer patients with various types of cancer and chemotherapy identified in the oncology unit of an urban tertiary hospital. Materials and Methods: Data were collected using questionnaires (demographic questionnaire, Medical characteristics, Memorial Symptom Assessment Scale (MSAS) and Brief COPE scales and analyzed for demographic, and disease-related variable effects on symptom prevalence, severity, distress and coping strategies. Results: Symptom prevalence was relatively high and ranged from 14.9% for swelling of arms and legs to 88.1% for lack of energy. This latter was the highest rated symptom in the study. The level of distress was found to be low in three domains. Problem-focused coping strategies were found to be more commonly employed compared to emotion-focused strategies, demonstrating significant associations with sex, age group, educational levels and race. However, there was a positive correlation between emotion-focused strategies and physical and psychological distress, indicating that patients would choose emotion-focused strategies when symptom distress increased. Conclusions: These findings demonstrate that high symptom prevalence rates and coping strategies used render an improvement in current nursing management. Therefore development of symptoms management groups, encouraging the use of self-care diaries and enhancing the quality of psychooncology services provided are to be recommended.

Image Quality Enhancement for Chest X-ray images (흉부 엑스레이 영상을 위한 화질 개선 알고리즘)

  • Park, So Yeon;Song, Byung Cheol
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.10
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    • pp.97-107
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    • 2015
  • The initial X-ray images obtained from a digital X-ray machine have a wide data range and uneven brightness level than normal images. In particular, in Chest X-ray images, it is necessary to improve naturally all of the parts such as ribs, spine, tissue, etc. These X-ray images can not be improved enough from conventional image quality enhancement algorithms because their characteristics are different from ordinary images'. This paper proposes to eliminate unnecessary background from an input image and expand the histogram range of the image. Then, we adjust the weight per frequency band of the image for improvement of contrast and sharpness. Finally, jointly taking the advantages of global contrast enhancement and local contrast enhancement methods we obtain an improved X-ray image suitable for effective diagnosis in comparison with the existing methods. Experimental results show quantitatively that the proposed algorithm provides better X-ray images in terms of the discrete entropy and saturation than the previous works.

A Study on the Interrelationship among Service Quality, Customer Satisfaction and Customer Loyalty by Distribution Channel, in the Dehumidifier Goods Industry (제습기산업의 유통경로별 서비스품질이 고객만족 및 고객충성에 미치는 상호관계에 대한 연구)

  • Kim, Kyusik;Ree, Sangbok
    • Journal of Korean Society for Quality Management
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    • v.42 no.4
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    • pp.665-684
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    • 2014
  • Purpose: The purpose of this study was to test and verify on the interrelationship among Service Quality, and Customer Satisfaction and Customer Loyalty in the Humidifier Goods industry. Especially, we study on the relative importance of each CS variables by distribution channel. Nowadays, most of manufacturing companies are proceeding the product servitization, which is combined service contents with product characteristics in the field of manufacturing industries. Methods: We surveyed humidifier purchaser about the some of CS variables and analyzed it using SPSS 21.0 and AMOS 21.0 as a statistical analysis tool. We use the frequency analysis, confirmatory factor analysis, multi-regression analysis and structural equation modeling analysis for our empirical study. Results: As the result of study, we find that Service Quality(SQ) influence Customer Satisfaction(CS) and CS influence Customer Loyalty(CL). Also, we verify that CS works mediate interaction on the effects between SQ and CL. And there are the significant relative effect of SQ to Customer Satisfaction in some of distribution channel. Conclusion: Finally, we make certain that the market size of the Humidifier goods industry will be increased rapidly. And the distribution channe l is more important to medium and small-sized enterprise. So, we have to pay attention to the study on the distribution channel of the Humidifier goods industry. And then, we expect more researches and studies on Service Quality and Customer Satisfaction in the field of manufacturing industries.