• Journal of radiological science and technology
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• v.38 no.1
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• pp.39-49
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• 2015

One of properties which X-ray and Neutron can be applied nondestructive test is penetration into the object with interaction leads to decrease in intensity. X-ray interaction with the matter caused by electrons, Neutron caused by atoms. They share applications in nondestructive test area because of their similarities of interaction mechanism. Grating interferometer is the one of applications produces phase contrast image and dark field image. It is defined by Talbot interferometer and Talbot-Lau interferometer according to Talbot effect and Talbot-Lau effect respectively. Talbot interferometer works with coherence beam like X-ray, and Talbot-Lau has an effect with incoherence beam like Neutron. It is important to expect the interference in grating interferometer compared normal nondestructive system. In this paper, simulation works are conducted according to Talbot and Talbot-Lau interferometer in case of X-ray and Neutron. Variation of interference intensity with X-ray and Neutron based on wave theory is constructed and calculate elements consist the system. Additionally, Talbot and Talbot-Lau interferometer is simulated in different kinds of conditions.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.57-65
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• 2015

Electronic packages consist of various materials, and as temperature changes, warpage occurs because of the difference in coefficient of thermal expansion. Shadow $moir{\acute{e}}$ is non-contact, whole field measurement technique for out-of-plane displacement. However, the technique has low sensitivity above $50{\mu}m/fringe$, it is not adequate for the warpage measurement in some circumstance. In this paper, by applying phase shifting process to the traditional shadow $moir{\acute{e}}$, measurement system having enhanced sensitivity of $12.5{\mu}m/fringe$ is constructed. Considering Talbot effect, the measurement is carried out in the half Talbot area. Shadow fringe pattern having four times enhanced sensitivity is obtained by the image process with four shadow fringes. The measurement technique is applied to the fibered package substrate and coreless package substrate for measuring warpages at room temperature and at about $100^{\circ}C$.

• Journal of Korea Water Resources Association
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• v.30 no.3
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• pp.225-233
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• 1997

The nonlinear effects on the statistical properties of wave groups in terms of the average nomber of waves in a group and the mean number of waves in a high run is studied in this paper utilizing the complex envelope and total phase function, random variable transformation technique and perturbation method. It tures out that the phase distribution is modified significantly by nonlinearities and it show systematic excess of values near the mean phase and the corresponding symmetrical deficiency on both sides away from the mean. for the case of threshold crossing rate, it turns out that threshold crossing rate reaches its maxima just below the mean water level rather than zero and considerable amount of probability mass is shifted toward the larger values of water surface elevation as nonlinearity is getting profound. Furthermore, the mean waves in a high run associated with nonlinear wave are shown to have larger values than the linear counterpart. Similar trend can also be found in the average number of waves in a group.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.93-100
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• 2012

A telemetry signal occurs the line-of-sight problem by the effect of geography in flight test. A fixed relay system or a mobile relay system is used to solve that problem in general but we propose an airborne telemetry relay system using aircraft in this paper. An airborne telemetry relay system receives the telemetry signal of the test vehicle and then retransmits it to the ground system. The receiving antenna which is a phased array antenna can be tilted to ${\pm}30^{\circ}$ beam direction by beam-forming and track the rapidly moving test vehicle in effect. The relay pod which is mounted to an aircraft consists of the front antenna and the side antenna. It receives S-band signal and then down-converts the frequency to L-band signal. As a result, that can remove the frequency interference on an aircraft while retransmitting.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.152-161
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• 2017

The CBTC(Communication based Train Control) system employed on 2.4GHz ISM band adopt the IEEE802.11.x standard. Therefor communication time delay, distortion and data losses will be produced. To overcome these problems, CPSK(Continuous Phase shift keying) modulated DS/SS(Direct Sequence Spread Spectrum) transmitter with 908MHz carrier frequency is proposed. Through the eye diagram and scatter diagram the performance is analysed. And the phase noise characteristic of the local oscillator is measured about 60dBc/Hz, this means that the phase noise performance is very good compared to the signal. Reference frequency suppression of the 2nd local oscillator is 50dB below compared to the signal. Through the polarities of the complementary signal equally probable, the line spectrum of the output spectrum is eliminated. The nonlinear effects which introduce the spectral spreading or spectral regeneration is reduced remarkably.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.250-256
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• 2008

In this paper, an X-band oscillator is presented using a new miniaturized microstrip hairpin resonator. The newly designed hairpin resonator on the microstrip line employs the spiral structure, which shows a higher loaded quality factor and the 50 % reduced circuit area compared to the conventional one at 9.2 GHz. The oscillator using proposed resonator shows the output power of 10.87 dBm, the second harmonic suppression of 41.99 dBc, and the phase noise performance of -101.49 dBc/Hz at 100 kHz offset, which is better than the conventional resonator oscillator by 6.17 dB.

• 한국해양학회지
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• v.28 no.3
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• pp.177-185
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• 1993

The theory for long wave scattering (Proudman, 1914: Longuet-Higgins, 1970) is applied to a tidal-frequency Kelvin wave propagating around a small cylindrical island in a shelf sea of uniform depth. The theory includes the effects of bottom friction on wave propagation. The theoretical analysis of the Kelvin wave around the island. this amplitude change results in a uniform amplitude of the total wave along the circumference of the island in an inviscid fluid, and the dynamic cause of this is explained in terms of Coriolis effects. Bottom friction attenuates the amplitude of the total wave from the frontal side of the island to the leeward side, but the amplitude variation along the coast becomes symmetric to the line connecting both idea. The phase of the scattered wave contributes to more rapid travel of the total wave in the front and leeward side than farther offshore. The effects of bottom friction on the wave phase around the island are negligible.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.26-32
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• 2006

다양한 정보기기들이 출현함에 따라 UI가 제품성공의 중요한 요인으로 부각되고 있다. 이러한 중요성을 인식하고 Microsoft, Nokia, HP, Motorola 등 해외 선진기업들은 UI 연구에 주력해 오고 있다. 국내 기업들도 2000년대부터 본격적으로 기업 내 UI팀을 구성하기 시작하여 점점 그 규모와 역할을 확대해 나가고 있지만, 개발시간의 촉박함, 체계적인 방법론에 대한 인식 부족, 전문인력부족 등으로 인해 UI업무가 효율적으로 진행되지 못하고 있다. 선진기업과 경쟁하기 위해서는 사용자 경험 측면에 대한 투자가 시급하며, 국내 UI전문가의 역할이 크게 요구되고 있는 시점이다. 따라서 기업 내 UI업무의 현주소를 파악하고 통합적인 고객체험 디자인을 목표로 하는 UI팀의 발전방향을 모색하고, 비전을 제시하는 것을 연구의 목적으로 삼는다. 본 연구의 방법으로는 문헌조사와 선행연구를 통해 UI, UX의 개념과 UI관련 조직의 구성과 역할을 살펴보고, 국내 모바일 및 전자제품 제조사, 유무선 인터넷을 기반으로 하는 컨텐츠 서비스 업체의 UI실무자를 대상으로 한 인터뷰와 설문조사를 통해 현재 기업 내 UI팀의 현황(조직구성, 업무의 범위 및 프로세스, 조직 내에서의 위상 등)을 분석하였다. 그 결과 다음과 같은 문제점들이 도출되었다. 첫째 조직구조상의 문제점, 둘째 업무 프로세스상의 문제점, 셋째 전문인력의 부족 등이다. 본 연구를 통해 기업 내 UI팀의 역할과 위상이 그 중요도에 비해 미약한 것으로 나타났다. 따라서 향후 통합적인 UX디자인을 접목한 미래 지향적 UI팀으로써 전체 프로세스 과정에 비전을 제시하기 위해서는 다양한 분야의 전문가들로 구성된 독립적 UI팀 구성이 이루어져야 한다. 또한 기획, 디자인, 개발 등 타 부서와의 보다 적극적인 업무교류를 통해 사용자의 입장을 대변하는 역할을 해야 한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.87-96
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• 2004

As a special concrete, which is a mixture of soil, cement and water, has strength like regular concrete for pavement, soil cement has been used in various field such as pavement and soft soil improvement. The objective of this study was to investigate the characteristic of unconfined compressive strength and time dependent behavior of soil cement that is made from decomposed granite soil or coluvial and inorganic solidification liquid. The results showed that the unconfined compressive strength appears to increase as the amount of cement and curing time increase In addition, the strength seems to decrease with increase of the potion of fine particles(No 200 sieve). The result of XRD indicated that there is Vermiculite, the product of reaction, in the soil cement. The dynamic properties of material, such as shear complex compliance, shear complex modulus, and phase angle could be calculated from the hysteresis loop obtained from the Haversine Creep Tests. Finally, creep behavior was able to be predicted from these dynamic properties.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.241-247
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• 2007

This paper introduces a new type push-push harmonic dielectric resonator oscillator. Proposed oscillators are utilized by HDRO(Harmonic Dielectric Resonator Oscillator) which are combined in push-push structure. As a result, fundamental signal suppression ratio and output power of harmonic signal has been improved. The increase of phase noise is compensated by improving coupling characteristic between resonator and parallel microstrip line. The proposed push-push HDRO shows the output power of 9.32 dBm, the fundamental signal suppression of -47.2 dBc and phase noise of -99.86 dBc at 100 kHz offset frequency and 18.7 GHz center frequency.