Earticle

우리는 도래각 (DoA; direction of arrival) 추정 방법 중 하나인 서로소 배열 기반의 프로퍼게이터 방법을 개선시키는 알고리즘을 제안한다. 서로소 배열 기반의 프로퍼게이터 방법은 특이값 분해없이 도래각을 추정하는 방법으로 서로소 배열 기반의 MUSIC에 비하여 현저히 낮은 복잡도를 지녔으나, 다소 저하된 도래각 추정 성능을 보인다. 우리는 이러한 성능 저하의 원인 중 하나로 잡음의 파워 스펙트럼 밀도를 포함하고 있는 신호의 자기상관행렬의 대각 성분이 사용되고 있지 않음에 있음을 파악하고, 잡음의 파워 스펙트럼 밀도가 장기간에 걸쳐 추정이 가능하다는 사실에 착안하여 신호의 자기상관행렬의 대각 성분을 사용하는 도래각 추정 방법을 제안한다. 우리는 시뮬레이션을 통해 우리가 제안한 방법이 기존의 서로소 배열 기반의 프로퍼게이터 방법보다 연산량을 4배정도 증가시키지만 탐지확률 95% 기준 하에 신호대 잡음비를 1.5dB, 도래각 분해능을 $0.7^{\circ}$ 만큼 개선시켜 그 성능이 서로소 배열 기반의 MUSIC에 보다 근접함을 관찰한다.

We propose an improved direction of arrival (DoA) estimation algorithm based on co-prime array and propagator method. The propagator method with co-prime array does not require singular value decomposition (SVD) requiring much less computational complexity but exhibiting somewhat worse performance in comparison with MUSIC based on co-prime array. We notice that one cause of the performance degradation was in the avoidance of the usage of the diagonal elements of the signal autocorrelation matrix that contains the noise power spectral density. So we propose an algorithm with the diagonal elements of the signal autocorrelation matrix based on the fact that the noise power spectral density can be estimated using noise observation over a long period of time. We observe, through simulations, that the proposed scheme in this paper improves the performance, with 4 times more computational requirement, by signal-to-noise ratio of 1.5dB and by DoA resolution of $0.7^{\circ}$ at the detection probability of 95% compared with the previously introduced co-prime array propagator scheme, resulting in performance much closer to that of co-prime array-based MUSIC scheme.

The micro barrier rip array structures have been applied in a variety of areas including as privacy films, micro heat sinks, touch panel and optical waveguide. The increased aspect ratio (AR) of barrier rip array structures is required in order to increase the efficiency and performance of these products. There are several problems such as burr, defect of surface roughness and deformation and breakage of barrier rip structure with machining high-aspect ratio micro barrier rip array structure using orthogonal cutting method. It is essential to develop technological methods to solve these problems. The optimum machining conditions for machining micro barrier rip array structures having high-aspect ratio were determined according to lengths ($200{\mu}m$ and $600{\mu}m$) and shape angles ($2.89^{\circ}$ and $0^{\circ}$) of diamond tool, overlapped cutting depths ($5{\mu}m$ and $10{\mu}m$), feed rates (100 mm/s) and three machining processes. Based on the optimum machining conditions, micro barrier rib array structures having aspect ratio 30 was machined in this study.

전력 소비량이 극대화 되면서 개인 전력 중개사업자 및 전력 생산설비의 증가에 따라 전력 설비를 유지, 보수하기 위한 현장 설비 담당자들을 위한 증강현실 기반 모니터링 시스템들에 대한 연구가 활발하게 진행되고 있다. 그러나 기존 증강현실 기반 모니터링 시스템들의 경우 외부 환경, 설비의 복잡성, 조명환경에 대한 간섭 등의 문제로 인하여 정확한 패턴 검출이 어려우며, 전력 설비에 대한 다양한 센싱 정보 및 서비스 정보를 하나의 패턴에 매칭하지 못하는 문제가 있다. 이로 인하여 전력 설비의 센서별로 단일 이미지의 패턴을 이용하여 센서 정보를 매칭하기 때문에 모든 정보를 증강하여 제공하기 위해 다수의 이미지 패턴이 필요하다. 본 논문에서는 다수의 특징 패턴들로 구성된 단일 이미지에서 특징 패턴들의 배열조합을 통해 다수의 정보를 매칭하여 제공하는 단일 이미지 패턴 배열화 기법을 제안한다.

As power consumption is maximized, research on augmented reality-based monitoring systems for on-site facility managers to maintain and repair power facilities is being actively conducted as individual power brokerages and power production facilities increase. However, in the case of existing augmented reality-based monitoring systems, it is difficult to accurately detect patterns due to problems such as external environment, facility complexity, and interference with the lighting environment, and it is not possible to match various sensing information and service information for power facilities to one pattern. there is a problem. For this reason, since sensor information is matched using a single image pattern for each sensor of a power facility, a plurality of image patterns are required to augment and provide all information. In this paper, we propose a single image pattern arrangement method that matches and provides a plurality of information through an array combination of feature patterns in a single image composed of a plurality of feature patterns.

우리는 서로소 배열 안테나에 기존의 프로퍼게이터 방법을 기반으로 하는 도래각 (DoA; direction of arrival) 추정 알고리즘을 제안한다. 서로소 배열 기법은 도래각 추정 해상도를 증가시키나 복잡도를 상호배열의 크기만큼 증가시킨다. 이러한 복잡도를 감소시키기 위하여 우리는 특이값 분해없이 도래각을 추정하는 프로퍼게이터 방법을 이용하는 방법을 제안한다. 우리는 시뮬레이션을 통해 선형 균일 배열 MUSIC, 선형 균일 배열 프로퍼게이터 방법, 서로소 배열을 이용한 MUSIC과 제안한 방법을 비교 및 분석하여, 우리가 제안한 방법이 복잡도가 훨씬 높은 서로소 배열을 이용한 MUSIC 보다는 약간 낮은 성능을 보이지만 나머지 기법들 보다는 훨씬 우수한 성능을 보임을 관찰한다.

In this paper, we propose a computationally efficient direction of arrival (DoA) estimation algorithm based on propagator method with non-uniform array. While the co-prime array techniques can improve the resolution of DoA, they generally lead to high computational complexity as the length of the coarray aperture. To reduce the complexity we use the propagator method that does not require singular value decomposition (SVD). Through simulations, we compare MUSIC with uniform lineary array, propagator method with uniform linear array, MUSIC with co-prime array, and the proposed scheme and observe that the performance of the proposed scheme is significantly better than MUSIC or propagator method with uniform linear array while it is slightly worse than computationally much more expensive co-prime array MUSIC scheme.

본 논문에서는 일본의 지명즈쿠시와 한국의 지명풀이 노래에 보이는 지명배열방식의 차이점과 특징에 대하여 살펴보았다. 그리고 그 결과, 지리적 연결성, 방향성, 언어유희성에있어서 한일양국간의 차이점이 확인되었다. 첫 번째로, 일본의 『구니 즈쿠시(国尽くし)』에 보이는 전통적인 지명배열방식에서는 인접한 지명과 지명을 마치 한 붓 그리기처럼 잇는 지리적 연결성이 보임을 알 수 있었다. 그리고 이 점은 부분적인 지리적 연결성이 보일 뿐, 전체적으로는 단절성이 보이는 『팔도읍지가(八道邑誌歌)』의 그것과 상이한 것이다. 두 번째로, 일본의 『구니 즈쿠시』에서는 모든 지명들이 교토에서 지방으로 멀어져 가는방향성(京→郷)과 더불어, 동일본의 모든 지명들은 서쪽의 교토를, 서일본의 모든 지명들은동쪽의 교토를 향하는 방향성(郷→京←郷)을 동시에 갖고 있음을 알 수 있었다. 그리고 이점은 국토를 남과 북, 동과 서, 좌와 우로 이분하는 한국의 지명배열 방식에서는 찾아보기힘든 특징이라 할 수 있다. 세 번째로, 『도카이도 오라이(東海道往来)』에 보이는 일본의 지명배열에서는 53개의 숙박지 지명이 끝말잇기 형태의 언어유희를 통해 마치 렌가(連歌)처럼 서로 긴밀하게 연결되는 반면, 『호남가(湖南歌)』 등에 보이는 한국의 지명배열에서는 동음이의어인 둘 혹은 네개의 지명들이 마치 한시(漢詩)처럼 대구를 이루며 연결되고 있음을 알 수 있다. 지명배열에서 보이는 한일 양국의 이러한 방식의 차이는, 비단 문학작품에서뿐만 아니라 오늘날의 행정구역, 시외전화 국번, 체전 입장순서, 우편번호에 대한 고려로 나타나고있다.

This paper tried to examine the differences and features the array system of Japanese and korean's toponymy(traveling) songs. And as a result, I was able to find the difference in three aspects, geographical connectivity, and directionality, to play on words in both Japanese and Korean's array system, First, We could see the method that Japanese kunizukushi(place name song) connects the cities and cities adjacent to a point and a line. Japanese kunizukushi has an overall uniformity and I defined that it is a geographical connectivity. But korean kunizukushi has a patial uniformity. It seems that the reason is came from korean's traditional idea that to divides country's administrative district into two. Paldo􋹲eupjiga is a good example. Second, Japanese kunizukushi has two types directionality, one is from Kyoto to country side, the other is from country side to kyoto. Japanese array system of toponymy directs all districts to countryside. But, on the other hand, every districts direct to kyoto. It does not conflict. Because every districts direct to their Emperor who live in kyoto. Third, Japanese kunizukushi has the method of to play on words, word chain game. This type's to play on words connect all place closely. It seems that this method similar to that Japanese continuous poem, lenga. But Korean kunizukushi connects every place name two by two, or four by four. This method looks like the couplet system of Chinese poetry.

본 논문에서는 원형 배열 안테나를 장착한 차량이 이동하면서 메쉬 네트워크 환경을 구성할 때 다중 노드 빔 형성을 위한 안테나 선택 방식과 전력 제어 알고리즘을 제안한다. 제안한 안테나 선택 방법은 안테나의 방사 이득을 고려하여 빔 형성을 위한 안테나를 선택하고, 두 개 이상의 노드가 인접할 경우 배열 이득을 최대화하기 위해 안테나를 중복으로 선택한다. 제안한 전력 제어 알고리즘은 중복 안테나 선택 시 SIR이 최대가 되도록 각 안테나의 전력을 제어한다. 전산 모의 실험을 통하여 제안한 알고리즘을 적용하여 기존의 방식과 비교하여 두 노드가 15°로 인접했을 때 최대 2.5 dB의 SIR 향상을 보인다.

This paper proposes the antenna selection scheme and power control algorithms of multiple nodes beamforming when the vehicles equipped with circular array antennas is moving and construct mobile mesh networks. The proposed antenna selection scheme chooses beamforming antenna elements considering antenna radiation gain and allows duplicated antenna selection for multiple adjacent nodes. The proposed power control algorithms maximize SIR for the duplicated antenna selection. The simulation demonstrates that the proposed antenna selection and power control achieve 2.5dB higher SIR gain than that of conventional methods when two nodes are apart from 15°.

본 논문에서는 원형배열 안테나의 위상차와 위상차 배열 패턴을 비교하여 전파 신호원의 방향을 찾는 방법을 연구 하였다. 위상비교 방향탐지 방식에서는 안테나 기준선 길이가 입사신호의 0.5파장보다 길면 같은 위상차에서 두 개 이상의 방위가 계산되는 방위각 모호성이 발생한다. 본 논문에서는 0-360도 방위각에서 전파 신호가 입사될 때 5개 안테나에서 검출된 위상차 패턴을 융합하여 방위각 모호성을 제거한다. 개발된 모호성 제거 기법은 안테나가 5개인 균일원형배열 구조 에서 안테나 기준선이 입사신호의 1.236파장 이하이면 방위각 모호성 없이 방향탐지를 정확하게 수행하였다. 본 알고리즘은 조난구조와 전자정보시스템의 방향탐지 장치 설계에 잘 활용할 수 있을 것으로 판단된다.

In this paper, we have studied a direction finding method of the radio signal by comparing the phase difference and its pattern from the uniform circular array antenna. In the phase comparison direction finding, if the length of the antenna baseline is longer than 0.5 wavelength of the incident signal, azimuth ambiguity occurs in which two or more azimuth angles are calculated in the same phase difference. The azimuthal ambiguity is removed by fusing the phase difference of the 5 antennas. The developed ambiguity elimination technology reduces the azimuth error where the antenna baseline is shorter than 1.236 wavelength in the uniform circular array with five antennas. This algorithm is very useful for the design of direction finder of an electronic information system.

위성통신시스템은 넓은 커버리지를 바탕으로 광범위한 지역에 통신을 가능하게 하는 장점을 가지고 있다. 그러나 위성통신 시스템에 할당된 주파수 대역의 사용률은 셀룰러 시스템과 같은 다른 무선통신시스템과 비교할 때 상당히 낮은 효율을 보인다. 그러므로 할당된 주파수를 이용하여 부가적인 서비스를 제공하고, 주파수 효율을 높이기 위한 방법들이 연구되고 있다. 본 논문에서는 허가 대역에서 새로운 서비스를 적용할 수 있는지에 관하여 분석해보고, 새로운 서비스를 적용하기 위하여 가장 중요한 부분인 위성 터미널의 신호를 정확하게 검출하는 방법을 제안한다. 제안하는 방법은 간섭을 회피하기 위하여 Spectrum Sensing과 Eigenvalue 검출하고, 결론을 통하여 터미널의 신호를 검출하고 성능을 분석한다.

The Satellite Mobile Communication System holds several advantages, such as wide coverage that guarantees the communication in a huge area. It is suitable in the ocean and forest and especially in emergency situation. However, the licensed frequency is not always occupied within all coverage and all the time. The actual utilization rate is relatively low compared to other wireless communications such as cellular systems. There are a large amount of white spaces in its coverage. Therefore, it is necessary to consider introducing additional services such as data communication, in order to increase the spectrum utilization as well as the revenue of the Satellite service provider. In this paper, we first analyze the possibility to implement new services in the licensed band of satellite mobile phone by its provider. Then we address the most significant issue for the implementation of current service, which is how to accurately detect the satellite mobile terminals. Finally, we suggest two new possible solutions namely, eigenvalue detection based methods to find out the existence of transmitted signal from the satellite mobile terminals.

본 논문에서는 256 능동위상배열 기반의 연직바람 관측장비(RWP)의 송수신 채널의 크기 및 위상을 보정하는 방법등이 논의된다. 별도의 모듈 추가 없이 송수신 전단기 및 송수신 전환기 에 커플러 및 스위치를 사용하여 송신 및 수신 보정 경로를 확보하였고, Gain 및 Phase Detector를 사용하여 256 송수신 채널의 크기 및 위상을 독립적으로 보정하였다. 보정된 256 능동위상배열 안테나는 근접전계 시험을 통해 5개의 빔 (연직, 동, 서, 남, 북)의 빔폭 및 사이드 로브가 시뮬레이 션 계산 값과 일치함을 확인하였다. 제안된 보정방법은 실외 환경에서 운용되는 능동위상배열 기반의 시스템에 용이하게 적용이 가능하다.

In this paper, the phased-array transceiver (TRX) channel amplitude and phase calibration method for a radar wind profiler (RWP) based on the 256 active phased array is discussed. Without the additional module, the TX and RX calibration paths were secured using couplers and switches in the TRX front ends and the TRX switching duplexers, and the amplitude and phase of the 256 TRX were calibrated using a gain and phase detector. The beam widths and side lobes of five beams (vertical, east, west, south, and north) of the calibrated 256 active phased array antenna were confirmed by a near-field which agreed well with the simulation results. The proposed calibration method can be easily applied to a system based on an active phased array operated in an outdoor environment.

지금까지는 Pollard의 Rho 알고리즘이 대칭키의 암호를 해독하는 이산대수 문제에 대해 가장 효율적인 방법으 로 알려져 있다. 그러나 이 알고리즘은 거인걸음 보폭 m = 「 p 」개의 데이터를 저장해야 하는 단점과 더불어 O( p ) 수행 복잡도를 보다 감소시킬 수 있는 방법에 대한 연구가 진행되고 있다. 본 논문은 이산대수의 사이클 검출을 위한 Nivasch의 스택 법의 데이터 갱신 횟수를 73% 이상 감소시키는 배열법을 제안하였다. 제안된 방법은 배열을 적용하였으며, ( xi < 0.5xi-1) ∩ (xi < 0.5(p-1)) 인 경우에 한해 배열 값을 갱신하는 방법을 적용하였다. 제안된 방법은 스택법과 동일한 모듈러 연산횟수를 보였지만 스택 법에 비해 이진탐색 법을 적용하여 배열 갱신 횟수와 탐색 시간을 획기적으로 감소시켰다.

Until now, Pollard's Rho algorithm has been known as the most efficient way for discrete algebraic problems to decrypt symmetric keys. However, the algorithm is being studied on how to further reduce the complexity of O( p ) performance, along with the disadvantage of having to store the giant stride m = 「 p 」 data. This paper proposes an array method for cycle detection in discrete logarithms. The proposed method reduces the number of updates of stack memory by at least 73%. This is done by only updating the array when ( xi < 0.5xi-1) ∩ (xi < 0.5(p-1)). The proposed array method undergoes the same number of modular calculation as stack method, but significantly reduces the number of updates and the execution time for array through the use of a binary search method.

The gene coding for carboxymethylcellulase (CMCase) of B. amyoliquefaciens DL-3 was isolated and cloned in E. coli JM109F. Rice bran and tryptone were chosen as carbon and nitrogen sources for production of CMCase by E. coli JM109F, respectively. Optimal conditions such as concentrations of carbon sources and nitrogen sources, initial pH of medium, and temperature for production of CMCase were investigated using L25(5)3 - orthogonal array method with five distinct levels and three factors. The highest production of CMCase was 1,314.2 U/ml from 5.0% (w/v) rice bran and 0.1% (w/v) tryptone under initial pH of 7.5 and 37℃. Optimal conditions of salts for production of CMCase were also investigated using L25(5)4. The highest production of CMCase E. coli JM109F was 1,514.6 U/ml with 0.5% (w/v) K2HPO4, 0.025% (w/v) NaCl, 0.04% MgSO4․7H2O and 0.24%(w/v) (NH4)2SO4.

Rice bran and peptone were the best combination of carbon and nitrogen sources for the production of CMCase by a psychrophilic marine bacterium, Psychrobacter aquimaris LBH-10. Based on intuitive analysis and statistical calculations using data from an L25 (54) orthogonal array experiment with four factors and five level of each factor, optimal concentrations of rice bran and peptone for the production of avicelase and CMCase by P. aquimaris LBH-10 were found to be 50.0 and 3.0 g/L, respectively, whereas those of FPase were 100.0 and 4.0 g/L, respectively. Optimal initial pHs of the medium for production of avicelase and CMCase were 8.0, whereas that of FPase was found to be 9.0. The optimal temperature for the production of avicelase, CMCase, and FPase was 30℃. According to R values calculated from results of the orthogonal array experiment, the most important factor for the production of cellualses by P. aquimaris LBH-10 was found to be rice bran. The optimal agitation speed and aeration rate for the production of CMCase in a 7 L bioreactor were 300 rpm and 1.0 vv. The highest production of avicelase, CMCase, and FPase from 50.0 g/L rice bran and 3.0 g/L peptone in a 100 L bioreactor under optimized conditions was 83.2, 388.7, and 75.4 U/mL, respectively.

Optimal conditions for production of the carboxymethycellulase (CMCase) and filterpaperase (FPase) by E. coli pTDL-3 were investigated in a 7L bioreactor using an orthogonal array method. On basis of intuitive analysis and statistical calculations using data, significance of aeration rate on production of the CMCase by E. coli pTDL-3 was higher than that of agitation speed on production of the CMCase as well as for production of the FPase. Optimal agitation speed and aeration rate for the production of CMCase were found to be 200 rpm and 1.0 vvm in a 7 L bioreactor. Productivity of the CMCase by E. coli pTDL-3 from 5.0% (w/v) rice bran and 0.1% (w/v) tryptone under optimized conditions was 544.4 U/ml in a 100 L bioreactor with an inner pressure of 0.2 kgf/cm2.

A microorganism hydrolyzing carboxymethylcellulose (CMC) was isolated from seawater, identified as Bacillus atrophaeus by analyses of 16S rDNA sequences, and named as B. atrophaeus LBH-18. Rice bran and ammonium peptone were the best combination of carbon and nitrogen sources for the production of the CMCase by B. atrophaeus LBH-18. Based on intuitive analysis and statistical calculations using data from an L25(35) orthogonal design experiment with three factors of rice bran, peptone, and initial pH of medium, rice bran was found to be the most important factor for production of the CMCase by B. atrophaeus LBH-18. Optimal concentrations of rice bran and peptone for production of CMCase were found to be 5.0% and 0.5%, respectively. Optimal initial pH of medium and temperature were 7.0 and 30℃. Effect of salts was also investigated using an orthogonal array method. Potassium phosphate from four salts in the medium was found to be the most important factor for production of the CMCase by B. atrophaeus LBH-18. Productivity of the CMCase by B. atrophaeus LBH-18 was about 120 U/ml under optimized conditions.

The optimal conditions for the mass production of carboxymethylcellulase (CMCase) of Bacillus amyloliquefaciens by a recombinant E. coli JM109/DL-3 were established in this study using an orthogonal array method. Rice bran and tryptone were found to be the best carbon and nitrogen sources for the production of CMCase by E. coli JM109/DL-3. The optimal concentrations of rice bran and tryptone and the initial pH for the production of CMCase were 50.0, 2.5 g/L, and 7.5, respectively. The optimal concentrations of K2HPO4, NaCl, MgSO4·7H2O, and (NH4)2SO4 in the medium for the production of CMCase by E. coli JM109/DL-3 were 5.0, 1.00, 0.40, and 0.60 g/L. The optimal agitation speed and aeration for cell growth of E. coli JM109/DL-3 in 7 L bioreactors were 500 rpm and 1.0 vvm, whereas those for the production of CMCase were 400 rpm and 1.0 vvm. The optimal inner pressure for cell growth of E. coli JM109/DL-3 in 100 L bioreactors was found to be 0.8 kgf/cm2, whereas that for the production of CMCase was 0.6 kgf/cm2. The production of CMCase with an inner pressure of 0.6 kgf/cm2 was 1.36 times higher than that without an inner pressure.

A microorganism isolated from seawater, which utilized rice bran as a substrate and produced carboxymethylcellulase (CMCase), was identified as Bacillus atrophaeus and designated B. atrophaeus LBH-18. Rice bran and peptone were found to be the best combination of carbon and nitrogen sources for cell growth of B. atrophaeus LBH-18 and the production of CMCase. Based on intuitive analysis and statistical calculations using data from an L25 (53) orthogonal array experiment with four factors and five level of each factor, the optimal concentrations of rice bran and peptone for cell growth of B. atropphaeus LBH-18 were 75.0 and 10.0 g/L, respectively, whereas those for the production of CMCase were 50.0 and 5.0 g/L, respectively. The optimal pH of the medium for cell growth were 6.0, whereas those for the production of CMCa se were 7.0. According to R values calculated from results of an orthogonal array experiment, the most important factor for cell growth as well as the production of CMCase by B. atrophaeus LBH-18 was found to be rice bran. The optimal temperature for cell growth for cell growth as well as the production of CMCase was 30℃.