• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1495-1498
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• 2008

We proposed driving method with variable integration time for ambient light sensing. One operation period of the proposed driving method consists of several sub-integration periods with variable integration time which can enlarge dynamic range of ambient light sensing circuit. Temperature dependent characteristic of p-intrinsic-metal (p-i-m) diode can be compensated using the proposed driving method.

• 한국통신학회논문지
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• 제33권7B호
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• pp.538-549
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• 2008

최근 IEEE 802.22 WRAN 워킹 그룹에서는 부족해지는 주파수 부족의 해결을 위해 CR (Cognitive Radio)의 기술개발을 진행 중에 있다. 채널을 센싱하는 방법에 따라 기존의 시스템 (IS: Incumbent System)의 보호에 상당한 영향을 미치기 때문에 네트워크 상황에 따른 최적의 센싱 방법을 선택하는 것이 중요하다. 이에 IEEE 802.22에서 fine sensing을 제안하고 있지만 아직까지는 다양한 네트워크에 효율적으로 적용할 수 없다. 따라서 본 논문에서는 네트워크 환경에 따라 효율적인 센싱 방법을 선택하기 위한 무선인지 네트워크에서 정책기반 채널 센싱구조 및 알고리즘 (Policy-based Channel Sensing Architecture and Algorithms for Cognitive Radio Networks)을 제안한다. 본 논문에서는 제안하는 채널 센싱 방법 및 알고리즘의 효율성을 확인하기 위하여 제시한 모의실험 결과는 각 센싱 방법에 따라 차이점을 보였지만 제안하는 채널 센싱 방법이 전체적으로 기존의 시스템 검출 시간 및 QP(Quiet Period)를 줄일 수 있었다. 제안하는 방법 중에 클러스터를 이용한 센싱 방법(Channel division round robin sensing)의 경우 IEEE 802.22에서 제안하는 fine sensing에 비교하여 70%정도 평균 검출시간을 줄일 수 있었다.

• 대한원격탐사학회지
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• 제27권6호
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• pp.743-752
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• 2011

One of main concerns of operators of the Earth observation satellite is taking images as many as possible under the constraints of satellite resources during fixed period. In order to achieve this goal, satellite operators are strongly required to generate the optimized image collection plans, and it is a very time consuming process to achieve an optimized image collection plan when it is done by manual. This paper suggests automation of image collection planning based on the dynamic programming algorithm to reduce the time required for image collection planning. The validity of the proposed method is tested using operating satellite system and the result is given in this paper.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1171-1173
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• 2003

There are two datasets to estimate the area-mean and time-mean precipitation rate. For one, an array of surface rain gauges represents a series of rods that have to the time axis of the volume. And another data is that of a remote sensing make periodic overpasses at a fixed interval such as radar. The problem of optimally combining data from surface rain gauge data and remote sensed data is considered. In order to combining remote sensed data with Automatic Weather Station (AWS), we use optimal weighting method, which is similar to the method of [2]. They had suggested optimal weights that minimized value of the mean square error. In this paper, optimal weight is evaluated for the cases such as Changma, summer Monsoon, Typhoon and orographic rain.

• Journal of Communications and Networks
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• 제16권2호
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• pp.238-244
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• 2014

A key technical challenge in TV white spaces is the efficient spectrum usage without interfering with primary users. This paper considers available spectrum discovery scheme using in-band sensing signal to support super Wi-Fi services effectively. The proposed scheme in this paper adopts non-contiguous orthogonal frequency-division multiplexing (NC-OFDM) to utilize the fragmented channel in TV white space due to microphones while this channel cannot be used in IEEE 802.11af. The proposed solution is a novel available spectrum discovery scheme by exploiting the advantages of a sensing signaling. The proposed method achieves considerable improvement in throughput and delay time. The proposed method can use more subcarriers for transmission by applying NC-OFDM in contrast with the conventional IEEE 802.11af standard. Moreover, the increased number of wireless microphones (WMs) hardly affects the throughput of the proposed method because our proposal only excludes some subcarriers used by WMs. Additionally, the proposed method can cut discovery time down to under 10 ms because it can find available channels in real time by exchanging sensing signal without interference to the WM.

• 대한원격탐사학회지
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• 제22권6호
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• pp.485-493
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• 2006

본 연구는 최적 결합 방법을 이용하여 다른 시공간 특징을 가진 강수량 자료를 통합하는 것이다. 최적 결합 방법은 AWS 우량계 자료와 S-band RADAR 추정 강수량을 전 시간대의 자신의 평균 제곱 오차에 반비례 하도록 디자인 하였다. 훈련시간에 따른 적절한 최적 가중치를 결정하기 위하여, 훈련시간을 1-10시간까지 실험하기 위하여 긴 기간 동안 비가 지속되었던 장마 사례에 적용하였다. 최적 결합 강수량의 수평장은 훈련시간 2시간 이후부터는 평탄화된 구조를 보여주었고, 최적 결합 강수량은 참값으로 가정한 종관관측 강수량과 수평 구조 및 값의 크기가 잘 일치하였다. 이러한 결과는 최적결합 방법이 다양한 자료들을 이용하여 고해상도의 강수량을 생산하는 데 사용할 수 있다는 것을 제시한다.

• 한국통신학회논문지
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• 제40권7호
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• pp.1347-1353
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• 2015

$0.13-{\mu}m$ CMOS 공정기술을 이용하여 10 Gb/s 4채널 수직공진 표면 광레이저 (VCSEL) 드라이버 어레이를 구현하였다. 높은 전류 해상도, 전력 소모 및 칩 면적의 향상을 위해 시분할 센싱기법을 사용한 디지털 APC/AMC가 최초로 채택되었다. 측정된 -3 dB 주파수 대역폭은 9.2 GHz이고, 소신호 이득은 10.5 dB, 그리고 전류 해상도는 폭넓은 온도 범위에 대해 10 Gb/s 까지 안정한 파장동작을 위한 1 mA/step이다. 제안된 APC/AMC는 5 ~ 20 mA 의 바이어스 전류 제어 및 5 ~ 20 mA 의 변조전류제어를 입증하였다. 4 채널 칩 소모전력은 최대 바이어스 및 변조전류 하에서 371 mW, 칩 사이즈는 $3.71{\times}1.3mm^2$이다.

• International journal of advanced smart convergence
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• 제10권3호
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• pp.33-40
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• 2021

Recently, wearable computers equipped with various biosensors such as smart watches, smart bands, and smart patches that support daily health management of users as well as patients have been released. Users of wearable computers such as smart watches face various difficulties in performing biometric information processes such as data sensing, collection, transmission, real-time analysis, and feedback in a weak wireless and mobile biometric information service environment. In particular, the biometric information collection interface is an important basic process that determines the quality and performance of the entire biometric information service. So far, research has focused on sensing hardware and logic. This study intensively considers the interface method for effectively sensing and collecting raw biometric information. In particular, the process of collecting biometric information is designed and analyzed from the perspective of periodicity. Therefore, we propose an efficient and stable periodic collection method.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.573-575
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• 2007

Current accuracy of GPS is within the meter level, which is sufficient for route guidance of car navigation system(CNS). But receiving condition of GPS signal varies time to time according to surrounding objects such as building, trees, and terrain. For this reason, the performance of the route guidance is degraded in urban region. In this paper, to improve the performance of the route guidance of CNS, we propose a method for determining location of vehicle using a location of the traffic signal and its pixel size extracted from real-time Image.

• 대한원격탐사학회지
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• 제23권5호
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• pp.375-383
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• 2007

This paper presents the method to provide a fast service for user in image manipulation such as zooming and panning of huge size high resolution satellite image(e.g. Giga bytes per scene). The proposed technique is based on the hierarchical structure that has 3D-Tiling in horizontal and vertical direction to provide the image service more effectively than 2D-Tiling technique in the past does. The essence of the proposed technique is to create tiles of optimum level in real time on the basis of current displaying area, which change as user manipulates huge image. Consequently, this technique provides seamless service, and will be very powerful and useful for manipulation of images of huge size without data conversion.