• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.161-169
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• 2010

According to the recent increase in air traffic more efficient air traffic control is required. This paper proposes the algorithm for efficient air traffic flow management. Aeronautical traffic environment is different from the common traffic environment since it needs vertical and horizontal separation deviation. In this paper used vincenty's fomula, we calculated distance of route for produced weight that was applied air traffic volume in distance of route using dijkstra algorithm. Then we let aircraft selects a course that minimize to wasting of fuel and time. As a simulation result, so unlilke simply shortest course calculation of existing course calculation algorithm, we confirmed that proposed algorithm in this paper can do air traffic control more efficiently by selecting optimized route.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.129-129
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• 2010

플라즈마 처리를 통하여 수직 합성된 다중벽 탄소나노튜브가 원뿔형 다발이 될 수 있으며 원뿔형 탄소나노튜브 다발은 기존의 구조적, 기계적 성질의 향상과 더불어 향상된 전계방출 능력을 가질 것으로 기대되어 이를 X-선원, 전계방출디스플레이(FED), 유기발광다이오드(OLED) 백라이트 등의 전자빔 원으로 적용하기 위한 연구가 진행되고 있다. 원뿔형 탄소나노튜브 다발의 형상 제어를 통하여 전계방출특성을 향상시킬 수 있으며 이를 위해 원뿔형 탄소나노튜브 다발이 생성되는 메커니즘과 조사되는 플라즈마의 역할에 대해서 이해하는 것이 중요하다. 본 연구에서는 플라즈마 생성부와 조사부를 분리한 유도결합형 플라즈마 원을 사용하여 입사되는 이온의 에너지, 조사량, 입자 종을 독립적으로 제어하였고 이를 통하여 원뿔형 탄소나노튜브 다발이 형성되는 메커니즘과 플라즈마의 역할을 밝혀내었다. 알곤 및 수소 플라즈마 처리에서는 원뿔형 탄소나노튜브 다발이 형성되지 않았으나 질소 및 산소 플라즈마 처리에서는 원뿔형 탄소나노튜브 다발이 형성되었다. 특히 산소 플라즈마 처리가 원뿔형 탄소나노튜브 다발 형성에 효과적이었다. 원뿔형 탄소나노튜브 다발의 형성 메커니즘은 탄소나노튜브의 분극과 쉬스 전기장의 상호작용을 이용한 모델을 사용하여 설명하였다. 질소 및 산소 플라즈마 처리에서는 탄소나노튜브 끝단에 생성되는 C-N, C-O 결합에 의해 향상된 유도 쌍극자와 쉬스 전기장에 의해 탄소나노튜브 끝단이 모여 원뿔형 탄소나노튜브 다발이 생성됨을 밝혀내었다. 산소 플라즈마 처리에서 입사되는 이온의 에너지 조절에 의한 쉬스 전기장 조절과 조사량 조절을 독립적으로 수행하여 원뿔형 탄소나노튜브 다발의 직경 및 높이가 쉬스 전기장 및 조사량에 따라 조절 가능함을 보였다. 이로부터 입사되는 이온의 입자 종, 쉬스 전기장 및 조사량 조절 등의 플라즈마 인자 조절을 통하여 원뿔형 탄소나노튜브 다발의 형상 제어가 가능함을 보였다. 탄소나노튜브의 형상 제어와 더불어 세슘 입자 삽입을 통한 탄소나노튜브의 일함수 감소를 통하여 향상된 전계 방출 특성을 갖는 탄소나노튜브 팁의 제조 가능성을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.883-888
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• 2007

일반적인 하천의 흐름방향으로 발생하는 주흐름(primary flow)에 중첩하여 주흐름 방향의 수직단면에 이차류(secondary flow)가 발생하게 되며 이러한 이차류의 발달은 투입된 오염물질의 횡혼합을 증대시킨다. 오염물질의 혼합은 이송(advection)과 확산(diffusion) 또는 분산(dispersion)의 과정으로 설명되며 본 연구에서는 수로전체의 혼합과정을 설명하기 위해서 이송 확산 방정식을 적용하였다. 본 연구에서는 실험수조를 $150^{\circ}$의 중심각을 갖는 S자 형태의 만곡수로를 제작하여 유량조건은 15, 30, $60\;{\ell}l/sec$의 세 가지 경우로, 수심은 15, 20, 30, 40 cm의 경우로 총 12 케이스의 실험을 수행하였다. 유속장의 측정은 Sontek사의 3차원 micro-ADV(Acoustic Doppler Velocimeter)를 이용하였다. 오염물질 확산실험은 소금물 용액에 주변수와의 밀도차를 없애기 위해서 메탄올 용액을 첨가하여 추적자로 이용하여 농도장의 분석을 일본 KENEK사의 전기전도도계(conductivity meter)와 Gartner사의 DAS(data acquisition system)를 이용하여 횡방향 유속장의 분포와 오염운의 거동을 비교하여 다음과 같은 결론을 얻게 되었다. 주 흐름은 직선구간에서는 중앙에서 최대 유속을 나타내며, 좌우대칭적인 유속분포의 모습을 보이고, 만곡부에서는 수로안쪽을 따라 최대유속이 발생하였다. 수로의 직선구간에서는 최대유속이 발생하는 즉, 중앙에서의 오염물질의 분산이 가장 활발하게 이뤄졌으며 농도의 퍼짐형상인 오염운 역시 만곡부에서는 수로만곡부의 안쪽을 따라 확산 이동함을 알 수 있었다. 만곡부 외측에서는 오염물질의 정체현상이 일시적으로 발생하며, 유속구조의 횡방향 비대칭구조로 인한 종 횡방향의 분리현상이 발생하고, 오염운의 중첩현상이 종방향으로 연속되게 나타난다. 향후 수심방향 거동을 포함한 3차원적 분석이 요구되며 이 연구결과는 2차원적 수치해석의 적용 및 분석 자료로써 이용이 가능하다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2325-2331
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• 2012

Planar square-spiral antenna using a strip conductor is proposed and analyzed for RFID system in UHF band operating from 860MHz to 960MHz. By varying the length of common line, detached distance, strip line-space, strip line-width and the number of spiral turn, the optimized antenna are designed and fabricated in compact size without a matching-stub between the input port of the proposed antenna and RFID tag chip. From the optimized results, the frequency bandwidth in VSWR<2 has covered 100MHz in the RFID UHF band. The antenna gain has obtained 3.5dBi at the center frequency of 910MHz and the desired beam pattern has shown directional pattern on elevation and azimuth angle. Therefore, the proposed antenna is suitable for practical RFID applications requiring various tag chips with the specific input impedance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.505-513
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• 2000

This study suggests new antenna design for polarization diversity. For dual polarization, two port feeding lines are printed on two separate layers and cross-shaped aperture is located on ground between the substrates. For reducing back radiation, a reflector is attached around $\lambda$/4 behind feeding substrates. For wide bandwidth we use a perturbed patch with saw tooth shaped. This perturbation effect causes reduction of antenna size and also reduction of array size. With the antenna proposed here, $1\times4$ array dual polarization antenna for polarization diversity of PCS base station is built. One single element has as large as 10.3%, 11.3% bandwidths at each port, V.S.W.R less than 1.3 and the isolation is less than -40 dB, also array antenna has 13.2% 12.7% band bandwidth, V.S.W.R less than 1.3 the isolation below -36dB and the XPD of 10 dB.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.46-52
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• 1998

In this paper, after inputting the computer with the attached number plate on the vehicle, using it, the color decomposition method and back propagation neural network proposed the extractable method of the vehicle number plate at high speed. This method separated R, G, B signal form input moving vehicle image to computer through video camera, then after transform this R, G, B signal into input image data of the computer by using color depth of vehicle number plate and store up binary value in the memory frame buffer. After adapting character's recognition algorithm, also improving this, by adapting back propagation neural network makes the vehicle number plate recognition system. Also minimalizing the similar color's confusion, adapting horizontal and vertical extracting algorithm by using the vehicle's rectangular architecture shows the extract and character's recognition of the vehicle number plate at high speed.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.175-182
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• 2013

This paper proposes a readability enhancement filter for Patterned Retarder (PR) display. In general, when some texts in stereoscopic images are shown on PR display, their readability tends to be lowered. In order to overcome this problem, we present a readability enhancement algorithm which consists of readability filtering stage and post-processing stage for specific characters. First, each input stereo image is divided into an odd line image and an even line image. Then, they are independently up-scaled vertically by using Lanczos filter. Next, two up-scaled line images are averaged considering vertical phase difference. In post-processing stage, two specific characters which are normally difficult to read on PR display are detected, and they are filtered for additional readability enhancement. Here, this additional filtering is based on a specific brightness adjustment, and is applied only for two characters. The experiment results show that the proposed method achieves significant improvement in terms of readability in comparison with the previous scheme.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.782-787
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• 2000

The monolithic single-pole three-throw(SP3T) GaAs PIN diode switch circuit for the broadband and high power application was designed, fabricated and characterized. To improve the power handling capability, buffer layers of the diode employ both low temperature buffer and superlattice buffer. The diode show the breakdown voltage of 65V and turn-on voltage of 1.3V. The monolithic integrated switch employed microstrip lines and backside via holes for low-inductance signal grounding. The vertical epitaxial PIN structure demonstrated better microwave performance than planar type structures due to lower parasitics and higher quality intrinsic region. As the large signal characteristics of the fabricated SP3T MMIC switch, the insertion loss was measured less than 0.6dB and the isolation better than 50dB when the input power was increased from 8dBM to 32dBm at 14.5GHz.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.171-179
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• 2002

The three-dimensional long-range dispersion model has been developed to understand the characteristics of the transport and diffusion of radioactive materials released into atmosphere. The model is designed to compute air concentration and ground deposition at distances up to some thousands of kilometers from the source point in horizontal direction. The vertical turbulent motion is considered separately within the mixing layer and above the mixing layer. The test simulation was performed In the area of Northeast Asia. The release point was assumed in the east part of China. The calculated concentration distributions art mainly advected toward the southeast part of release point by the wind fields. The developed model will be used to estimate the radiological consequences against a nuclear accident. The model will be supplemented by the comparative study using the data of the long-range field experiments.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.17-20
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• 2008

As a part of a research program to study the shear reinforcement of flat plate system, this investigation aimed to determine the effect of shear reinforcement type on punching shear strength of monolithic slab-column connection. A total of 5 specimens were fabrication and tested. The dimension of the slab were $2.63{\ast}2.725{\ast}0.18m$, with a centrally located column $0.6{\ast}0.8m$ in cross section. Experimental results showed that the CFS shear reinforcement was not effective because of lack of proper bond with concrete. 3 shear reinforcement except of CFS showed high effectiveness, which resulted in a considerable increment of the punching shear resistance of the connection.