Earticle

본 논문에서는 10.3GHz(x-band) 주파수에서 동작하는 단일 및 2-패치 마이크로스트립 배열 안테나 설계 및 시뮬 레이션 결과를 제시하였다. 전송선로 이론을 통한 패치와 급전 선로 설계 파라미터를 구하였고 CST MWS를 사용하여 마이 크로스트립 패치 배열 안테나를 최적화 설계하는 과정을 제안하였다. 먼저 단일 마이크로스트립 패치 안테나를 설계한 후 최적의 반사 손실 및 이득을 얻기 위해 CST MWS를 사용하여 각 파라미터를 최적화하였다. 그리고 X-대역 애플리케이션 을 위한 2×1 마이크로스트립 배열 안테나로 설계를 확장하였다. 사용된 기판은 Roger RO4350B(h=0.79mm, Er = 3.54 ) 이고 급전 방식은 안테나 크기와 급전 효율을 고려하여 인셋(inset) 급전 방식을 사용하였다. CST MWS를 활용한 시뮬레이 션 결과를 제시하였으며, 동작 주파수(10.3GHz)에서 -18dB의 S11, 10.2dBi의 이득, 0.165GHz의 대역폭, 30o(Az, φ=0), 121o(El, φ=90)의 3-dB 빔폭을 얻었다. 향후 본 연구 결과를 기본으로 4×4 어레이로 추가 확장하여 안테나를 설계 및 제작하여 다양한 X-밴드 애플리케이션에 활용될 수 있다.

This paper presents a single and 2-patch microstrip array antenna operated on a frequency of 10.3GHz(x-band). It outlines the process of designing a microstrip patch array antenna using CST MWS. Initially, a single microstrip antenna was designed, followed by optimization using CST MWS to attain optimal return losses and gain. Subsequently, the design was expanded to create a 2×1 microstrip inset-fed array antenna for the X-band applications. The construction material is Roger RO4350B, with specific dimensions (h=0.79mm, Er = 3.54). The achieved results include an S11 of -18dB at the resonant frequency (10.3GHz), a gain of 9.82dBi, a bandwidth of 0.165GHz, and a 3-dB beamwidth of 30o, 121o in Az(φ=0) and El(φ=90) plane, respectively. The future plan involves the fabrication of this array antenna and further expansion to a 4×4 array of microstrip antennas. It is then incorporated on the X-band applications for practical uses.

본 논문은 기존에 사용되어지는 직진성이 강한 LED가 광학계와 결합되었을 때의 단점을 보완 개선하기 위한 연구이다. 직신성이 강한 LED를 조사면에 비추었을 때 패턴이 형성되는 것을 극대화시키기 위해서 전반사 렌즈를 사 용하였다. 렌즈와 채결된 LED PKG를 1개만 배열하여 조사면에 비추었을 때, 8개를 일렬 배열하여 조사면에 비추었을 때, 8개를 팔각 배열했을 때로 나눠 시뮬레이션을 진행하였다. 시뮬레이션 결과 데이터 중 Luminous Intensity RGB 차 트로는 조사면에 비추어진 배광 패턴을 비교‧분석하였다. 배광 분포 곡선에서는 수평, 수직에서의 각을 비교하여 수치 적인 개선 방법 연구를 수행하였다. 본 연구를 통해서 조명 기구에서 생길 수 있는 패턴을 LED PKG의 배열을 통해서 상쇄시킬 수 있다는 것을 고안하였으며, 이 방법으로 PCB를 제작하면 실용적으로 렌즈의 성능을 향상시킬 수 있고, 금 형 제작 비용을 절감할 수 있을 것으로 사료된다.

This paper is a study to improve and complement for defects when LEDs with strong linearity which are conventionally used are combined with the optical system. A Total reflection lens was used to maximize the formation of the pattern when the directivity LED was illuminated on the illuminated surface. When only one LED PKG decided to be lens and picked up was irradiated on the illuminated surface, simulation was carried out by dividing it into three arranged when eight were arrayed side by side and illuminated on the illuminated surface, and eight LEDs arranged in octagonal arrangement it was. In the simulation result data, the luminous intensity RGB chart compares and analyzes the light distribution pattern displayed on the illuminated surface. We studied numerical improvement method of light distribution curves by comparing horizontal and vertical angles. Through this study we devised that patterns that can occur in lighting fixtures can be canceled via the arrangement of LED PKGs and we fabricated PCBs in this way parctically we can improve the performance of the lens, it can be considered that it is possible th reduce the cost of metal mold production.

배열형 DBMS는 배열형 자료의 저장 및 분석이 가능하므로 과학자들로부터 많은 기대를 받고 있다. 본 논 문은 배열형 DBMS를 이용하여 위성원격탐사 영상을 처리하는 방법의 기술이다. 하지만 기존의 연구 방법들은 크게 두 가지 문제가 있다. 첫째, 지구곡률 등에 의해 왜곡된 데이터가 그대로 시각화되는 문제를 가진다. 둘째, 기 작성 된 질의를 통해 얻어진 시각화 결과를 다른 분석에 활용하기 어렵다. 따라서 본 논문은 이런 문제점을 해소하고 더 나아가 기존의 2차원 시각화가 아닌 위성원격탐사 영상의 3차원 시각화 방법을 제안한다. 아울러 논문의 세부적인 연구내용은 다음과 같다. 첫째, 위성원격탐사 영상을 배열 데이터베이스에 저장, 분석, 가공하는 방법을 기술한다. 둘 째, 가공된 결과물의 3차원 시각화 방법을 제안한다. 마지막으로 본 논문의 학술적 기여도는 배열형 DBMS에서의 위성원격탐사 영상의 활용 방법과 함께 위성데이터의 3차원 시각화 기법을 제안했고, 위성원격탐사 영상의 활용범위 확대에 기여할 것으로 요약된다.

An array DBMS has been expected widely from scientists because it is convenient to store and analyze the data of array type. In this paper, we describe how to handle satellite remote-sensing images in the array DBMS. However, previous works in their visualization have two problems as follows. First, the images are visualized as a state of distorted by the curvature of the earth. Second, it is difficult to apply the results of visualization by pre-written queries to other analyses. Therefore, this paper proposes a three dimensional visualization method of satellite remote-sensing images, not traditional 2D visualization. Our research contents are as follows. First, we describe how to store, process, and analyze the satellite remote-sensing images in the array DBMS. Second, we propose a three-dimensional visualization method for their processed outputs. Lastly, our contributions can be summarized that we propose a method of handling satellite remote-sensing images in the array DBMS and their 3D visualization techniques. It is also expected that their use be available widely in many industrial areas.

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 연구는 6 Dof(Degrees of freedom) 지원 가상현실 재현을 위한 3차원 기하정보 기반 Mesh Data 변 환 및 CG/실사 기반 영상 합성 기술을 통해 공간콘텐츠를 효과적으로 제작할 수 있는 새로운 방안을 제안한다. 기존 가상현실 콘텐츠는 CG기반 콘텐츠 제작 기술이 주로 활용되었으나 사실적인 실감콘텐츠 구현을 위해서는 실사 기반 3차원 공간 구성이 필수적이다. 본 논문에서는 2D Arrary 영상을 기반으로 전경 및 배경 영상을 3차 원 공간콘텐츠로 구성하여 실사 기반 실감형 가상현실 콘텐츠를 제작하였다. 실측 공간과 가상현실 공간 정합도를 계산하여 3차원 공간 구성의 정확도를 측정하였다. 향후 LF(Light Field) 영상 및 디지털 트윈 기술을 적용하여 실감형 가상현실 콘텐츠를 제작하는데 활용 수 있다.

This study proposes a new method to effectively create spatial contents through 3D geometry based mesh data transformation and CG / real image based synthesis technology for 6 Dof (Degrees of freedom) support. Conventional virtual reality contents are mainly used for CG-based content production technology, but due to the real-based 3D space construction is essential for realizing realistic contents. Based on the 2D Arrary image, the foreground and background images were composed of 3D spatial contents to produce photo realistic virtual reality contents. The accuracy of three-dimensional spatial composition was measured by calculating the degree of matching between the measured space and the virtual reality space. In the future, it can be used to produce realistic virtual reality contents by applying LF image and digital twin technology.

본 논문에서는 MSB(Most Signigicant Bit)를 활용하여 CDAC(Capacitor Digital to Analog Converter) Array를 구동하는 12비트 축차 비교형 아날로그-디지털 변환기 설계를 제안한다. 본 연구는 MSB를 활용하여 제 어 로직으로 CDAC 구동 전류를 감소하고 전력 소모를 하지 않는 비교기의 비동작 구간으로 저전력을 구현하여 SAR ADC(Successive Approximation Analog to Digital Converter)를 설계하였다. 제안하는 SAR ADC의 구조 와 동작 원리를 설명하며 Cadence Tools를 이용하여 설계하고 결과에 대한 시뮬레이션을 추가하였다. 본 논문에서 설계한 SAR ADC는 180nm CMOS 공정을 사용하고 1.8V의 공급 전압으로 동작한다. 샘플링 속도는 0.2MS/s이 며 SNR(Signal to Noise Rate)은 69.2dB, ENOB(Effect Number of Bit)는 11.2bit, 크기는 0.396mm2, 전력 소모 는 0.19mW를 소비하여 저전력으로 동작하며 높은 해상도를 갖는다.

In this paper, we propose a design of a 12-bit SAR ADC (Successive Approximation Analog-to-Digital Converter) that drives CDAC (Capacitor Digital to Analog Converter) Array by utilizing MSB (Most Significant Bit). In this study, the CDAC driving current is reduced with control logic using MSB, and low power is implemented in the non-operating period of the comparator that does not consume power. The proposed SAR ADC (Successive Approximation Analog to Digital Converter) is designed, the structure and operating principle is explained, and simulation of the design and results is added using Cadence Tools. The SAR ADC designed in this paper uses a 180nm CMOS process and operates with a supply voltage of 1.8V. The sampling rate is 0.2MS/s, SNR (Signal to Noise Rate) is 69.2dB, ENOB (Effect Number of Bit) is 11.2bit, core area of 0.396mm2, and power consumption is 0.19mW, therefore, it operates with low power and has high resolution.

Steering vector and covariance matrix estimation mismatch along with moving jammer/platform, can affect the performance of null-steering beamformer. In this paper, by utilizing null-widening, null-deepening and diagonal loading shrinkage in space?time adaptive processing (STAP) structure, two methods for nullifying GNSS (global navigation satellite system) jamming/interference in cruise moving platforms are introduced. The enhanced performance of the proposed methods is investigated through numerical simulations. The results indicate improvement in the number of acquired GNSS satellites, in heavy jamming (GNSS denied) scenario, by reconstructing and acquiring at least 87% of satellites.

This paper considers a broadband multicell system with key characteristics that base-stations and relays employ beamforming via large antenna arrays, as well as in-band full duplex relay operation. The signal to interference plus noise ratio gain (which is in excess of the maximum required for such a system) could be exploited either for reducing self-interference or the backhaul and access link transmitted powers. The presented results indicate that with a moderate front-to-back-ratio scenario for the antenna array, “small” antenna arrays with 8 elements can lower the requirement of full duplex self-interference cancellation by up to 55 dB, while large antenna arrays of 1024 elements will produce 100 dB reduction. Alternatively, for the same scenario, both the backhaul and access transmitted powers could be reduced by ∼55 dB and ∼25 dB with 1024 elements.

Nowadays, research works into the dynamic and static human activities on Smart spaces abounds. Artificial Intelligence (AI) and low cost non-privacy invasive ambient sensors have made this ubiquitous. This review presents a state-of-the-art analysis, performance evaluation, and future research direction. One of the aims of activity recognition (especially that of humans) systems using thermal sensors and AI is the safety of persons in Smart spaces. In a Smart home, human activity detection systems are put in place to ensure the safety of persons in such an environment. This system should have the ability to monitor issues like fall detection, a common home-related accident. In this work, a review of trends in thermal sensor deployment, an appraisal of the popular datasets, AI algorithms, testbeds, and critical challenges of the recent works was provided to direct the research focus. In addition, a summary of AI models and their performance under various sensor resolutions was presented.

Fractal arrays are repetitive-geometry-based smart arrays having impressive array factor properties. However, the performance of these arrays degrades owing to their large number of antenna elements at higher expansion levels. This research work presents the thinning of Sierpinski fractal arrays while keeping an applicable balance between all array factor properties by using two types of bounded binary-fractal-tapering techniques known as Sierpinski and Haferman carpet anti-diagonal tapering techniques. Approximately 22% to 50% of antenna elements are thinned in each successive iteration of the Sierpinski fractal array with the proposed tapering techniques.

Climate change has worsened droughts and floods, and created conditions more likely to lead to pathogen contamination of surface water and groundwater. Thus, there is a growing need to disinfect livestock water. Ultraviolet (UV) irradiation is widely accepted as an appropriate method for disinfecting livestock water, as it does not produce hazardous chemical compounds and kills pathogens. However, UV-based disinfection inevitably consumes electricity, so it is necessary to improve UV disinfection effectiveness. Aluminum-based reflective nanolens arrays that enhanced the effectiveness of a continuous-flow UV water disinfection system were developed using electrochemical and chemical processes, including electropolishing and two-step anodization. A continuous UV disinfection system was custom designed and the parts were produced using a three-dimensional printer. Electropolished aluminum was anodized at 40 and 80 V in 0.3 M oxalic acid, at 120 and 160 V in 1.0 M phosphoric acid, and at 200 and 240 V in 1.5 M citric acid. The average nanolens diameters (D) of the aluminum-based reflective nanolens arrays prepared using 40, 80, 120, 160, 200, and 240 V anodization were 95.44, 160.98, 226.64, 309.90, 296.32, and 339.68 nm, respectively. Simple UV reflection behind irradiated water disinfected Escherichia coli O157:H7 in water more than did the non-reflective control. UV reflection and focusing behind irradiated water using an aluminum-based reflective nanolens array disinfected E. coli O157:H7 more than did simple UV reflection. Such enhancement of the UV disinfection effectiveness was significantly effective when a nanolens array with D 226.64 nm, close to the wavelength of the irradiated UV (254 nm), was used.

This paper provides a space temporal interference cancellation method for ultra wide-band (UWB) communication systems based on combination of tapped delay line array antenna and orthogonal matched filter. In order to reduce the interference from the other system using overlapping frequency band, space domain signal processing such as an array antenna has been proposed. However, principal array antenna cannot be applied to impulse radio (IR) UWB because IR-UWB does not have carrier signal. In this paper, we propose a novel tapped delay line array antenna combined with orthogonal matched filter detector. From the numerical evaluation, we show that the proposed system can make null direction to face to the interference signal direction. Additionally, we show that the proposed system can reduce interference signal even if the interference signal has equivalent pulse shape and equivalent incoming direction.

Since most studies for estimating an angle-of-arrival (AOA) based on the antenna array have considered the antenna array with a single configuration, they are not proper to simultaneously estimate AOAs of multiple signals with various frequencies. In this paper, we introduce a cascade AOA estimation technique consisting of CAPON and Beamspace Multiple Signal Classification (MUSIC), based on a Combined Array Antenna (CAA) with Uniform Rectangular Frame Array (URFA) and Uniform Circular Array (UCA), for enhancing the above problem. In addition, we provide the computational complexity analysis for showing the low computational complexity of this technique comparing to the conventional technique.

Genetic screening is being widely applied to trace the origin of global developmental delay or intellectual disability. The 5q14.3 microdeletion has recently been uncovered as a clinical syndrome presenting with severe intellectual disability, limited walking ability, febrile convulsions, absence of speech, and minor brain malformations. MEF2C was suggested as a gene mainly responsible for the 5q14.3 microdeletion syndrome. We present the case of a 6-year-old girl, who is the first patient in Korea with de novo interstitial microdeletions involving 5q14.3, showing the typical clinical features of 5q14.3 microdeletion syndrome with a smaller size of chromosomal involvement compared to the previous reports. The microdeletion was not detected by subtelomeric multiplex ligation-dependent probe amplification, but by array comparative genomic hybridization, which is advisable for the detection of a small-sized genetic abnormality.

This paper newly proposes a direct antenna array control approach to reduce channel spatial correlation for multiuser spatial multiplexing. Conventional rectangular arrays can form three dimensional beams and have superior signal separation performance compared to linear arrays. However, when the arrival angles of some signals are close, the signal separation (interference cancellation) performance deteriorates since the projection points onto horizontal/vertical axes of several antenna elements overlap and spatial resolution along each axis is degenerated. The key proposal is to improve signal separation performance by mechanically changing the positional relationship of antenna elements. The proposed scheme can achieve better Bit Error Rate (BER) performance by searching the optimal antenna rotation angle.

Detection of estrus is an essential factor as a method of successful breeding in the sow. As increasing the adaption of the information and communication technology (ICT) into swine industry, this study focuses on a possibility and quantification of standing time, vulva and body temperature as methods of estrus detection, comparing each time and temperature in estrus and non-estrus period, and analyzing each success rate of new and existing methods. Ultrasonic sensor array and digital infrared thermography were used to evaluate whether new methods such as standing time and number, and vulva and skin temperature can be replaced, or these methods can be quantifiable in estrus period. Ultrasonic sensor array was installed beside the stall and digital infrared thermography was placed in the rear of sow to collect the dates of sow in estrus and non-estrus period. This study showed total standing time, number and number over 10 minutes, and vulva temperature of the sow in estrus period were increased (p < 0.05) compared with those of sow in non-estrus period, respectively. Detection of estrus using standing time and vulva temperature tended (p = 0.06) to increase the success rate when artificial insemination (AI) was performed. In conclusion, standing time and vulva temperature increased when estrus happened. Success rate of AI of sow using these methods showed an increasing trend. Therefore, existing method using the naked eye can be replaced to new method such as vulvar temperature and standing time when detecting the estrus.