• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.7 s.110
• /
• pp.659-664
• /
• 2006

This paper reports a high power 60 GHz push-push oscillator fabricated using $0.12{\mu}m$ metamorphic high electron-mobility transistors(mHEMTs). The devices with a $0.12{\mu}m$ gate-length exhibited good DC and RF characteristics such as a maximum drain current of 700 mA/mm, a peak gm of 660 mS/mm, an $f_T$ of 170 GHz, and an $f_{MAX}$ of more than 300 GHz. By combining two sub-oscillators having $6{\times}50{\mu}m$ periphery mHEMT, the push-push oscillator achieved a 6.3 dBm of output power at 59.5 GHz with more than - 35 dBc fundamental suppression. The phase noise of - 81.5 dBc/Hz at 1 MHz offset was measured. This is one of the highest output power obtained using mHEMT technology without buffer amplifier, and demonstrates the potential of mHEMT technology for cost effective millimeter-wave commercial applications.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.12
• /
• pp.1-5
• /
• 2009

In this paper, low phase noise push-push oscillator (OSC) using the metamaterial resonator for missile defense systems and satellite communication was design and implemented. The metamaterial resonator has the large coupling coefficient value, which makes a high Q value, and has reduced phase noise of OSC. The OSC with 1.8 V power supply has phase noise of -117 dBc/Hz @100 kHz in the 12 GHz. When it has been compared with metamaterial resonator and coventional spiral resonator, the reduced Q value has been -29.7 dB and -47.6 dB respectively. This low phase noise OSC using metamaterial resonator could be available to a OSC in X-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.8
• /
• pp.847-853
• /
• 2007

In this paper, a novel push-push voltage-controlled oscillator(VCO) using microstrip square open loop resonator and tunable negative resistance is presented. The microstrip square open loop resonator has the large coupling coefficient value, which makes a high Q value, and has reduced phase noise of VCO. The VCO with 1.8V power supply has phase noise of $-124.67{\sim}-122.67dBc/Hz\;@\;100 kHz$ in the tuning range, $5.744{\sim}5.859 GHz$. The FOM of this VCO is $-202.83{\sim}-201dBc/Hz\;@\;100 kHz$ in the same tuning range. When it has been compared with single-ended VCO using microstrip square open loop resonator, and push-push oscillator using microstrip line resonator, the reduced phase noise has been -8.51dB, and -33.67dB, respectively.

• The Journal of the Korea Contents Association
• /
• v.21 no.2
• /
• pp.462-473
• /
• 2021

With the development of society, changes in the family structure of China's residents and the increase in family income, parent-child travel has gradually become a new hotspot for tourism consumption. It is important for tourism marketers to understand the needs and motivations of parent-child travelers. This study explored the push and pull motivations of parent-child travelers by conducting a questionnaire survey of 290 travelers to parent-child farms and validated the path relationships between push and pull motivations, experiences and behavioral intentions. The result indicated that: 3 push factors were derived from the factor analysis of 13 push items and were named as 'For children & Family', 'Escape & Relax', and 'Socialization'; 3 pull factors were derived from the factor analysis of 11 pull items and were labeled: 'Facilities & Safety', 'Theme activities', and 'Environment'. Through sub hypotheses testing, the results show that push-pull motivation of parent-child travelers has a positive effect on their experience(4Es) for attending. 'Esthetics Experience' has the highest effect on the parent-child travelers' behavioral intentions, followed by 'Education Experience' and 'Entertainment Experience'.

• Journal of Industrial Convergence
• /
• v.21 no.4
• /
• pp.123-131
• /
• 2023

The purpose of this study was to investigate difference of activity of scapular stabilizer muscles among push-up, knee push-up and wall push-up exercise. Eight male college students were recruited as participants without any history of shoulder or pathology. The results showed that serratus anterior, anterior deltoid, infraspinatus were higher muscle activities than other scapular stabilizer muscles during push-up exercise and muscle activity of standard push-up exercise was higher muscle activity than that of Knee and Wall push-up exercise. Also, We know that knee push-down exercise was more effective than wall push-down exercise for scapular stabilization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.7
• /
• pp.613-624
• /
• 2002

Electrical characteristics of two types of 20 GHz Push-Push GaAs MESFET dielectric resonator oscillators having Wilkinson and T-junction power combiners for the output stage have been investigated and compared. So we have explained that the output power and phase noise properties of the Push-push FET DRO are depending on return loss and isolation characteristics of power combiner at the fundamental and the second harmonic frequencies. A Push-push oscillator for suppressing the fundamental frequency of 10 GHz and enhancing the second harmonic of 20 GHz has been designed and fabricated in microstrip configuration on 20 mil thick RT-Duroid($\varepsilon$$_{r}$ = 2.52) Teflon substrate. Return loss and isolation characteristics of T-junction and Wilkinson have been measured at the fundamental frequency of 10.2 GHz and the second harmonic frequency of 20.5 GHz. At the fundamental frequency, -12 dB return loss and -3.7 dB isolation have been measured for the T-junction power combiner, and -14 dB return loss and -11 dB isolation fur the Wilkinson power combiner. At the second harmonic frequency, -10 dB return loss and -7.5 dB isolation have been obtained for the T-junction power combiner, and -23 dB return loss and -22 dB isolation for the Wilkinson power combiner. As a result, we have confirmed that the oscillator based on the Wilkinson power combiner with better retrun loss and isolation characteristics produces more output power and better phase noise characteristics..

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.5
• /
• pp.1289-1295
• /
• 2008

Recently, it is progressing a study for supporting various application services using OpenAPI(Application Program Interface). But it is not enough a study related OpenAPI(Open Application Interface) to access many collected context data of sensor networks for ubiquitous application services. Therefor, this paper presents Pull/Push service model based on sensor networks, and implements OpenAPI fer Pull/push application services. And, we design and implement OpenAPI using web service for Pull application services. This Pull OpenAPI supports users the context data of temperature and humidity using the remote service based on .Net framework in sensor networks. And, we design and implement OpenAPI using TCP/IP socket interface for Push application services in sensor network. This Push OpenAPI provides users a state of temperature, humidity collecting in sensor networks. Consequently, user can develop easily various application services as supporting OpenAPI instead of closed application interface of sensor networks based on existed specific database.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.06d
• /
• pp.306-310
• /
• 2010

인터넷에서 정보를 제공하는 일반적인 형태는 클라이언트의 요청에 따라 웹 서버가 응답하여 제공하는 방식이다. 이러한 전통적인 방식은 클라이언트의 명시적인 요청에 따라 정보가 제공되기 때문에 급변하는 정보를 클라이언트가 적시에 제공받기에는 불편함이 따른다. 이러한 문제를 해결하기 위하여 다양한 연구들이 시도되고 있으며, Server Push는 전통적인 방식의 문제점을 극복하기 위하여 웹 서버에서 정보가 변할 때마다 클라이언트로 적시에 정보를 제공하는 방식이다. 본 논문에서는 Server Push 기반의 웹 어플리케이션 개발을 효과적으로 지원하는 Java Push Engine에 대하여 기술한다. Java Push Engine은 자바 기반으로 구현되어 플랫폼에 독립적인 Push 어플리케이션 개발을 지원하며, 다중화 통신을 지원하여 많은 클라이언트의 요청을 동시에 처리 할 수 있다. 또한 Java Push Engine과 함께 효과적인 비동기 통신을 수행하는 Push 클라이언트를 개발하기 위함 Ajax 기반의 Java Push Engine Java 스크립트에 대해서도 기술하다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.2
• /
• pp.514-525
• /
• 1996

In this paper, Push-push Osciplier(Oscillator + Multiplier) has been analyzed by even-odd mode analysis method. A 10GHz DRO, an Osciplier using 10GHz DRO design method and an Osciplier using even-odd mode analysis method were designed, fabricated and tested to verify this method. The measured results verified the validity of the analysis method using even-odd mode analysis.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2000.04a
• /
• pp.36-39
• /
• 2000

멀티미디어 통신 시스템은 멀티미디어의 특성상 대용량 데이터를 처리하기 위한 버퍼 관리기법이 요구된다. 버퍼에 있는 데이터를 전달하는 방식에는 데이터를 제공하는 서버가 데이터 흐름을 제어하는 Push 방식과 데이터를 제공받는 클라이언트가 데이터 흐름을 제어하는 Pull 방식이 있다. 그러나 RTP를 사용하는 기존의 멀티미디어 통신 시스템의 경우 서버와 클라이언트 사이에 Push 방식과 Pull 방식 중의 하나만을 제공하기 때문에 다양한 미디어의 재생을 지원하기에는 한계가 있고, 인터렉티브한 통신이 불가능하다. 더욱이, Push/Pull 두 가지 방식을 모두 지원한다하더라도 단일화된 버퍼 구조를 제공하지 않아 메모리 사용의 낭비가 있다는 단점이 있다. 이를 해결하기 위하여 , 본 논문에서는 RTP를 사용하는 멀티미디어 통신환경에서 각각 단일화된 버퍼구조 구조를 가지고 있는 서버와 클라이언트 사이에 Push 방식과 Pull 방식의 전송방식을 모두를 지원할 수 있는 통합된 Push/Pull 전송 모델을 제안한다. 이 기법은 서버와 클라이언트 사이에서 Peer-to-Peer 개념으로 인터랙티브한 Push/Pull 전송을 지원할 뿐만 아니라 일관된 인터페이스를 지원하는 단일 버퍼 구조를가짐으로써 시스템의 메모리 효율을 향상시킬 수 있다.