• 대한전자공학회논문지TC
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• 제47권11호
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• pp.19-23
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• 2010

본 논문에서는 MIMO 시스템에서 부분 증분 리던던시 방식 Hybrid ARQ를 위한 결합 기법을 제안한다. 제안 결합 기법은 부분 증분 리던던시 방식 Hybrid ARQ에서 반복 전송되는 정보 심볼들을 위한 심볼 레벨 결합 기법이다. 본 논문에서는 제안 결합 기법이 반복 전송되는 정보 심볼들뿐 아니라 매 전송마다 새로이 전송되는 패리티 심볼들의 검출 성능 또한 향상시킴을 보인다. 모의실험 결과를 통해 제안된 결합 기법이 특히 Zero Forcing 검출 사용 시에 기존의 비트 레벨 결합 기법보다 부분 증분 리던던시 방식 Hybrid ARQ의 성능을 크게 향상시킴을 확인하였다.

• 응용통계연구
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• 제33권6호
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• pp.683-696
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• 2020

표본의 다범주 표현형을 예측하는데 사용되는 최적의 유전자집단이란 적은 수의 유전자로 표현형을 정확히 예측할 수 있는 유전자들의 모임이다. 특이발현유전자를 검색하는 통계량은 이미 여러 가지가 있고, K-평균 군집화를 곁들여 중복성이 적은 특이발현유전자들을 선택 가능하다. 이들을 바탕으로 적은 수로 정확하게 다범주 분류가 가능한 유전자집단을 구성할 수 있도록 수정한 입자최적화 방법을 제안한다. 널리 알려진 ALL 248례와 SRBCT 83례를 이용하여 제안된 방법으로 최적유전자집단을 찾을 수 있음을 보였다.

• 한국군사과학기술학회지
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• 제17권3호
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• pp.336-341
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• 2014

When using a higher-order modulation scheme, there are variations in bit-reliability depending on the bit position in a modulation symbol. Variations of bit-reliability in the codeword block lower the decoding performance. Also, the decoding performance increases as the sum of the bit-reliabilities in the codeword block increases. This paper presents a novel hybrid automatic repeat request scheme that increases the sum of the reliabilities of the transmitted bits by lowering the modulation order, and decreases the variations of bit-reliability in the codeword block by preferentially retransmitting bits with low reliability. The proposed scheme outperforms the constellation rearrangement scheme. Furthermore, the proposed scheme also provides a good solution in cases where the size of the retransmission block is smaller than the size of the initial transmission block.

• 한국통신학회논문지
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• 제21권9호
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• pp.2317-2327
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• 1996

Original binary image can be reconstructed without any distortion by MS(morphological skeleton) image. Though we reduce some points in a MS image, there is no problem to reconstruct original image by it. And then, there are two methods of LMS and GMS which reduce the redundant points of a MS image. The redundancy degree of a GMS image is zero and it is less than that of LMS. And then, GMS image is the best thing of the three kinds of morphological skeleton image to enhance the compression efficienty by the Elias code. But there are continous SKF=1 points in a GMS image whenever using 2 dimensional structureing element. Those points in a GMS image gives rise to a bad compression efficiency. And then, solving this problem, this paper proposes hybrid structuring elements algorithms for binary image compression.

• ETRI Journal
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• 제33권5호
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• pp.759-769
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• 2011

Cooperative hybrid-automatic repeat request (HARQ) protocols, which can exploit the spatial and temporal diversities, have been widely studied. The efficiency of cooperative HARQ protocols is higher than that of cooperative protocols because retransmissions are only performed when necessary. We classify cooperative HARQ protocols as three decode-and-forward-based HARQ (DF-HARQ) protocols and two amplified-and-forward-based HARQ (AF-HARQ) protocols. To compare these protocols and obtain the optimum parameters, two unified frameworks are developed for protocol analysis. Using the frameworks, we can evaluate and compare the maximum throughput and outage probabilities according to the SNR, the relay location, and the delay constraint. From the analysis we can see that the maximum achievable throughput of the DF-HARQ protocols can be much greater than that of the AF-HARQ protocols due to the incremental redundancy transmission at the relay.

• Journal of Semiconductor Engineering
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• 제2권1호
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• pp.99-108
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• 2021

Successive Approximation Register (SAR) Analog-to-Digital Converters (ADC) seem to become the hottest ADC architecture during the past decade in implementing energy-efficient high performance ADCs. In this overview, we will review what kind of circuit techniques and architectural advances have contributed to place the SAR ADC architecture at its current position, beginning from a single SAR ADC and moving to various hybrid architectures. At the end of this overview, a recently reported compact and high-speed SAR-Flash ADC is introduced as one design example of SAR-based hybrid ADC architecture.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.34-42
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• 2006

As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires(steer-by-wire) should be fault tolerant because a failure can come without any warning and its effect is devastating. In order to make system fault tolerant, there has been a body of research mainly from aerospace field. This paper presents the structure of predictive smoothing voter that can filter out most erroneous values and noise. In addition, several numerical simulation results are given where the predictive smoothing voter outperforms well-known average and median voters.

• ETRI Journal
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• 제42권3호
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• pp.388-398
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• 2020

We herein propose a heuristic redundancy selection algorithm that combines resubmission, replication, and checkpointing redundancies to reduce the resiliency overhead in fault-tolerant workflow scheduling. The appropriate combination of these redundancies for workflow tasks is obtained in two consecutive phases. First, to compute the replication vector (number of task replicas), we apportion the set of provisioned resources among concurrently executing tasks according to their needs. Subsequently, we obtain the optimal checkpointing interval for each task as a function of the number of replicas and characteristics of tasks and computational environment. We formulate the problem of obtaining the optimal checkpointing interval for replicated tasks in situations where checkpoint files can be exchanged among computational resources. The results of our simulation experiments, on both randomly generated workflow graphs and real-world applications, demonstrated that both the proposed replication vector computation algorithm and the proposed checkpointing scheme reduced the resiliency overhead.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2684-2686
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• 2000

This paper describes a preliminary study on a modeling technique for control performance evaluation of asynchronous TMR(Triple Modular Redundancy) controller. Hybrid system modeling is applied to TMR controller performance evaluation and mixed logical dynamical system description is used to model the behavior of majority voter in the controller. Windup and bumpless transfer problems in redundancy controls are also mentioned.

• 전자공학회논문지B
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• 제30B권7호
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• pp.14-23
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• 1993

This paper proposes an algorithm to reduce the bitrate for transmission of MCP(motion compensated prediction) error signals. Many digital image coders have recently employed hybrid coding schemes which perform motion compensation, DCT transform, quantization, and variable length coding. The variable length coding compresses the quantized DCT coefficient data by removing their statistical redundancy. But some DCT blocks have the interblock statistical redundancy as well as the intrablock one. To utilize both of them, the DCT blocks are classified into the interleaving group and the non-interleaving group. And then each DCT blocks in the interleaving group are is encoded independently, and the DCT blocks in the interleaving group are encoded after interleaving the DCT coefficients. Through the simulations, it is shown that the proposed method outperforms the conventional method in which each DCT block is encoded independently.