• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.311-313
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• 2002

We are under development of a 3D PET scanner with depth of interaction (DOI) capable of high sensitivity and high resolution. In this scanner, a maximum data transfer rate of coincidence pair's event information is 10 Mcps and one event is a 64-bit data format. This maximum data transfer rate corresponds by 10 times a conventional PET scanner. A data acquisition system, which fulfills the specification of this scanner, is considered for parallel collection with banks including several coincidence units. Data transfer rate is improved by optimizing parameters of a message size, and so on.

• 대한전자공학회논문지TC
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• 제39권3호
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• pp.117-124
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• 2002

고해상도 위성 영상 레이다(SAR)에서 획득한 대용량의 레이다 영상신호는 주어진 임무시간 내에 실시간으로 지상에 전송해 주어야 하기 때문에 위성탑재 영상 레이다의 고속 데이터 전송 능력이 시스템의 성능을 결정하는 중요한 요인이 되고 있다. 본 논문에서는 소형 경량의 위성 SAR의 임무 요구 조건을 만족하고, 위성 영상 레이다의 운용모드에 따라 고해상도에서 광역모드에 이르기까지 광범위한 데이터를 고속으로 처리할 수 있는 멀티 채널 데이터 전송모듈 설계에 관하여 논한다. 주어진 위성 데이터 링크 모델을 바탕으로 링크 버짓과 영상 모드별 데이터 전송률을 분석하고, 시스템의 요구 전송율과 오차율을 만족하는 온 보드 영상 자료 저장기, 자료 처리기, 송신기 및 전송 안테나의 설계 결과를 제시하고 성능을 분석하였다. 본 설계에 적용된 고속 채널 모듈은 고속자료 전송이 요구되는 위성 및 항공기 탑재 데이터 링크의 성능확장에 효과적으로 활용될 수 있다.

• 한국정보통신학회논문지
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• 제24권9호
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• pp.1241-1244
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• 2020

In this paper, we consider a downlink non-orthogonal multiple access system with a base station and N mobile stations, where we assume that instantaneous channel state information (CSI) is available at the base station. A power allocation scheme is proposed to achieve perfect fairness, which means equal data rates for all mobile stations. However, the power allocation scheme using full CSI requires high complexity. Hence, a simple power allocation scheme with low complexity is proposed by using high signal-to-noise power ratio (SNR) approximation. The simple power allocation scheme can achieve perfect fairness only for high SNR. However, it needs only the best CSI and the simple procedure to obtain power allocation coefficients. From simulation results, we show that the simple power allocation scheme provides remarkable fairness performance at high SNR.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.154-159
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• 2003

본 논문에서는 ITU G.726 규격을 만족하는 표준형 ADPCM 부호화 법을 이용하여 배경잡음의 크기에 따라 음성의 부호화율이 두가지로 가변하도록 함으로써, 낮은 데이터 전송률을 가지고도 단일 부호화율의 경우보다 개선된 음질을 갖는 부호화 기법을 제안하였다. 이를 위하여 배경잡음보다 큰 음성신호에 대하여는 데이터의 양이 커지더라도 음질을 향상시키기 위하여 40 [Kbps]로 압축하고, 작은 음성신호에 대하여는 16[Kbps]로 압축하여 데이터의 양을 줄이도록 하여 전체적으로 압축데이터의 양을 줄이면서 음질을 개선하도록 하였다. 입력된 음성신호에 대하여 두가지 압축율을 결정하기 위하여 영교차율(ZCR)을 사용하여 처리속도를 빠르도록 하였다.

• 전기학회논문지
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• 제59권5호
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• pp.996-1000
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• 2010

In order to apply VLC (visible light communication) in harsh environment of nuclear power plant in-containment building, the high luminance LEDs, which are key components of the VLC system, have been gamma irradiated at the dose rate of 4 kGy/h during 72 hours up to a total dose of 288 kGy. The radiation induced coloration effect in the high luminance LED bulb made of acryl or plastic material was observed. In the VLC wireless data transmission experiment using the high luminance LEDs irradiated by high dose rate gamma-ray, the radiation induced coloration effect of the high luminance LED bulb extended the communication distance compared to non-irradiated LEDs.

• 한국통신학회논문지
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• 제25권12B호
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• pp.2109-2119
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• 2000

In this paper, the Packet CDMA Reservation ALOHA protocol is proposed to support the multi-traffic services such as voice and videophone services with handoff calls, high-rate data and low-rate data services efficiently on the multi-rate transmission in uplink cellular systems. The frame structure, composed of the access slot and the transmission slot, and the proposed access permission probability based on the estimated number of contending users for each service are presented to reduce MAI. The assured priority to the voice and the videophone handoff calls is given through higher access permission probability. And through the proposed code assignment scheme, the voice service can be provided without the voice packet dropping probability in the CDMA/PRMA protocols. The code reservation is allowed to the voice and the videophone services. The low-rate data service uses the available codes during the silent periods of voice calls and the remaining codes in the codes assigned to the voice service to utilize codes efficiently. The high-rate data service uses the assigned codes to the high-rate data service and the remaining codes in the codes assigned to the videophone service. Using the Markov-chain subsystem model for each service including the handoff calls in uplink cellular systems, the steady-state performances are simulated and analyzed. After a round of tests for the examples, through the proposed code assignment scheme and the access permission probability, the Packet CDMA Reservation ALOHA protocol can guarantee the priority and the constant QoS for the handoff calls even at large number of contending users. Also, the data services are integrated efficiently on the multi-rate transmission.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.298-300
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• 2005

Satellite payload on-board date compression unit are use for saving date storage space and reducing time to transmit payload data to the ground station. The KOMPSAT-3 payload will generate higher data rate than KOMPSAT-2 due to its better ground sample distance capacity. High input data rate and limited output transmission data rate might lead excessive compression and degraded image quality. This paper presents a trade-off study about data storage capacity and compression parameters for estimated KOMPSAT-3 system.

• 한국통신학회논문지
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• 제29권3A호
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• pp.293-302
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• 2004

무선랜은 무선으로 근거리 단말들을 연결하는 통신 기술로, 일반적인 무선랜의 구성은 하나의 AP와 하나 이상의 단말 기기가 BSS를 구성한다. 무선랜 서비스 영역에서 AP와 거리가 가까운 단말은 고속의 데이터 전송률을 보장받을 수 있지만 AP에서 거리가 멀리 떨어진 단만은 신호의 세기가 약해지므로 고속데이터 전송률의 보장을 받을 수 없는 단점을 가지고 있다. 본 논문에서는 무선 단말 중 일부를 중계 단말로 이용함으로써 그룹화를 통해 고속데이터 전송을 가능하게 하는 방법을 제안하고, 시뮬레이션을 통해 무선 단말의 그룹화를 위해 제안한 깊이우선탐색 알고리즘과 넓이우선탐색 알고리즘을 비교, 분석하였다. 그 결과 넓이우선탐색 알고리즘이 무선 단말을 위한 그룹화에 보다 효과적인 알고리즘임을 보였다.

• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.513-517
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• 2013

Recently, maskless lithography (ML) systems have become popular in digital manufacturing technologies. To achieve high-throughput manufacturing processes, digital micromirror devices (DMD) in ML systems must be driven to their operational limits, often in harsh conditions. We propose an instrument and algorithm to detect DMD malfunctions to ensure perfect mask image transfer to the photoresist in ML systems. DMD malfunctions are caused by either bad DMD pixels or data transfer errors. We detect bad DMD pixels with $20{\times}20$ pixel by white and black image tests. To analyze data transfer errors at high frame rates, we monitor changes in the frame rate of a target DMD pixel driven by the input data with a set frame rate of up to 28000 frames per second (fps). For our data transfer error detection method, we verified that there are no data transfer errors in the test by confirming the agreement between the input frame rate and the output frame rate within the measurement accuracy of 1 fps.

• 대한지역사회영양학회지
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• 제4권3호
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• pp.421-430
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• 1999

A neural network system was applied in order to analyze the nutritional and other factors influencing chronic diseases. Five different nutrition evaluation methods including SD Score, %RDA, NAR INQ and %RDA-SD Score were utilized to facilitate nutrient data for the system. Observing top three chronic disease prediction ratio, WHR using SD Score was the most frequently quoted factor revealing the highest predication rate as 62.0%. Other high prediction rates using other data processing methods are as follows. Prediction rate with %RDA, NAR, INQ and %RDA-SD Score were 58.5%(diabetes), 53.5%(hyperlipidemia), 51.6%(diabetes), and 58.0%(diabetes)respectively. Higher prediction rate was observed using either NAR or INQ for obesity as 51.7% and 50.9% compared to the previous result using SD Score. After reviewing appearance rate for all chronic disease and for various data processing method used, it was found that iron and vitamin C were the most frequently cited factors resulting in high prediction rate.