• 한국정보통신학회논문지
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• 제17권9호
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• pp.2174-2182
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• 2013

본 논문에서는 LED 기반 VLC 통신시스템의 기술동향 및 국제표준인 IEEE 802.15.7의 PHY 기술을 분석하였다. 또한, PHY I mode의 세부기술을 분석하고 RS 부호 및 블록 인터리버를 설계함으로써 시스템의 복잡도 분석 및 가시광 무선채널 환경에서의 수신 성능을 분석하였다. 결과에 의하면, Single mode로 운영되는 PHY I의 경우, 짧은 메시지 전송이라는 환경에 비해 시스템 설계의 복잡도가 크다는 것을 확인할 수 있었고, 다중경로 가시광 채널환경에서는 1.5dB의 수신 SNR이 추가적으로 요구됨을 확인할 수 있었다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권2호
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• pp.43-51
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• 2021

As the number of mobile devices has been increasing tremendously, system capacity should be enlarged in future next generation communication, such as the fifth-generation (5G) and beyond 5G (B5G) mobile networks. For such future networks, non-orthogonal multiple access (NOMA) has been considered as promising multiple access technology. In this paper, to reduce both latency and complexity in existing NOMA, we propose non-successive interference cancellation (SIC) NOMA with asymmetric binary pulse amplitude modulation (2PAM), nearly without bit-error rate (BER) loss. First, we derive the closed form of BER expressions for non-SIC NOMA with asymmetric 2PAM, especially under Rayleigh fading channels. Then, it is shown that the BER performance of the stronger channel user who is supposed to perform SIC in conventional NOMA can be nearly achieved by the proposed non-SIC NOMA with asymmetric 2PAM, especially without SIC. Furthermore, we also show that the BER performance of the weaker channel user in conventional NOMA can be more closely achieved by the proposed non-SIC NOMA with asymmetric 2PAM. These BERs are shown to be achieved over the part of the power allocation range, which is consistent with the NOMA principle of user fairness. As a result, the non-SIC NOMA scheme with asymmetric 2PAM could be considered as a promising NOMA scheme toward next generation communication.

• 산업경영시스템학회지
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• 제42권3호
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• pp.242-251
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• 2019

The purpose of this study was to identify the relationship between complexity, tacit knowledge, know-how, perception, and perception on business performance, and to suggest management implications for corporate performance and organizational executives. Therefore, the implications of this study are as follows. First, corporate representatives and staff in charge of organization should be able to access various information and contents through various routes about the work of members of the organization, and should make efforts to freely communicate among members. Second, corporate representatives and organizational practitioners should consider using the traditional methods of communication within their work, but allowing more informed and inmates to do more off-the-job activities that can increase intimacy with each other. Third, corporate representatives and organizational practitioners should provide a situation in which they can acquire work knowledge in a variety of ways, but must devise communication methods to increase information sharing and information value among members. Fourth, corporate representatives and organizational practitioners should endeavor to provide employees with educational support, family invitation events, awards and bonuses, and compliments that will make them more interested in their work. Lastly, corporate representatives and organizational practitioners are encouraged to maintain effective communication, employee pride, etc., so that the concentration of work, achievement, quality and productivity of work, and high professionalism can be maintained. You will have to work hard.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권6호
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• pp.2240-2254
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• 2021

We investigate the channel allocation problem in an ultra-dense device-to-device (D2D) enabled cellular network in underlaying mode where multiple D2D users are forced to share the same channel. Two kinds of low complexity solutions, which just require partial channel state information (CSI) exchange, are devised to resolve the combinatorial optimization problem with the quality of service (QoS) guaranteeing. We begin by sorting the cellular users equipment (CUEs) links in sequence in a matric of interference tolerance for ensuring the SINR requirement. Moreover, the interference quota of CUEs is regarded as one kind of communication resource. Multiple D2D candidates compete for the interference quota to establish spectrum sharing links. Then base station calculates the occupation of interference quota by D2D users with partial CSI such as the interference channel gain of D2D users and the channel gain of D2D themselves, and carries out the channel allocation by setting different access priorities distribution. In this paper, we proposed two novel fast matching algorithms utilize partial information rather than global CSI exchanging, which reduce the computation complexity. Numerical results reveal that, our proposed algorithms achieve outstanding performance than the contrast algorithms including Hungarian algorithm in terms of throughput, fairness and access rate. Specifically, the performance of our proposed channel allocation algorithm is more superior in ultra-dense D2D scenarios.

• ETRI Journal
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• 제45권6호
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• pp.963-973
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• 2023

Non-orthogonal multiple access (NOMA) is considered a key candidate technology for next-generation wireless communication systems due to its high spectral efficiency and massive connectivity. Incorporating the concepts of multiple-input-multiple-output (MIMO) into NOMA can further improve the system efficiency, but the hardware complexity increases. This study develops an energy-efficient (EE) subchannel assignment framework for MIMO-NOMA systems under the quality-of-service and interference constraints. This framework handles an energy-efficient co-training-based semi-supervised learning (EE-CSL) algorithm, which utilizes a small portion of existing labeled data generated by numerical iterative algorithms for training. To improve the learning performance of the proposed EE-CSL, initial assignment is performed by a many-to-one matching (MOM) algorithm. The MOM algorithm helps achieve a low complex solution. Simulation results illustrate that a lower computational complexity of the EE-CSL algorithm helps significantly minimize the energy consumption in a network. Furthermore, the sum rate of NOMA outperforms conventional orthogonal multiple access.

• 한국인터넷방송통신학회논문지
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• 제20권1호
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• pp.107-112
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• 2020

본 연구에서는 IEEE 802.1 time sensitive network(TSN) task group(TG)에서 표준화 중인 asynchronous traffic shaping (ATS) 기술에서 제시된 minimal interleaved regulator(IR) 개념을 확장 적용한 통합 플로우 기반 지연시간 보장 프레임워크를 분석하였다. 해당 프레임워크는 단위 네트워크의 출력포트에 IR을 적용하여 burst 축적을 방지하면서, 동시에 단위 네트워크 안에서는 입출력 포트를 기준으로 플로우를 통합하여 복잡도를 낮출 수 있다. 본 연구에서는 다양한 파라미터들 가진 네트워크에서의 수치적 분석을 통해서, 제안된 낮은 복잡도의 프레임워크의 성능이 기존 integrated services (IntServ) 프레임워크보다 더 우수하거나 비슷함을 보였다. 특히 통합 플로우의 크기와 단위 네트워크의 크기가 클수록 성능이 우수해짐을 확인하였다.

• ETRI Journal
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• 제39권4호
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• pp.570-581
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• 2017

Multiplication in finite fields is used in many applications, especially in cryptography. It is a basic and the most computationally intensive operation from among all such operations. Several systolic multipliers are proposed in the literature that offer low hardware complexity or high speed. In this paper, a bit-parallel polynomial basis systolic multiplier for generic irreducible polynomials is proposed based on a modified interleaved multiplication method. The hardware complexity and delay of the proposed multiplier are estimated, and a comparison with the corresponding multipliers available in the literature is presented. Of the corresponding multipliers, the proposed multiplier achieves a reduction in the hardware complexity of up to 20% when compared to the best multiplier for m = 163. The synthesis results of application-specific integrated circuit and field-programmable gate array implementations of the proposed multiplier are also presented. From the synthesis results, it is inferred that the proposed multiplier achieves low power consumption and low area complexitywhen compared to the best of the corresponding multipliers.

• 한국정보전자통신기술학회논문지
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• 제4권1호
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• pp.9-16
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• 2011

본 논문은 다수의 비트레이트에서 변환하는 멀티레이트 변환 기능을 효율적으로 실현할 수 있는 비디오 트랜스코더를 제안하고자 한다. 이것을 구현하기 위해서는 부호 및 역 양자화기를 하나의 처리기로 공유해야 할 뿐만 아니라 유사한 재양자화 스텝값을 가지고 있는 출력 사이에 재양자화-재부호화 처리기를 공유시킴으로서 멀티레이트 변환시에 처리량을 감쇄시킬 수 있는 구조를 제안하고자 한다. 또, 이론적 평가 및 평가에 따른 실험 결과로부터 제안한 방식인 재양자화-재부호화기의 공유 방법이 출력 수에 대한 처리량을 효율적으로 감쇄시킴으로서 단일 레이트의 출력의 경우보다 약 3~6배의 처리량으로도 임의의 출력 수에 대응할 수 있는 결과를 얻을 수 있었다.

• 한국정보통신학회논문지
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• 제19권8호
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• pp.1839-1844
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• 2015

Low-density parity-check(LDPC) 코드는 우수한 에러 정정 능력으로 인해 점점 많은 통신 표준에서 채택되고 있으며 그 중 구현이 용이한 quasi-cyclic LDPC(QC-LDPC)가 많이 사용되고 있다. QC-LDPC 복호기에서는 데이터들을 rotation할 수 있는 cyclic-shifter가 필요하며, 이 cyclic-shifter는 다양한 크기의 rotation을 수행할 수 있어야 한다. 이러한 cyclic-shifter를 multi-size circular shifter(MSCS)라고 부르며, 이 논문에서는 MSCS를 적은 면적으로 구현한 구조를 제안한다. 기존의 직렬로 배치된 barrel-rotator 구조에서 rotation의 성질을 이용하여 필요 없는 멀티플렉서를 가려내고 이들을 제거함으로써 저면적을 구현하였다. 실험 결과 면적을 약 12% 줄일 수 있었다.

• 한국멀티미디어학회논문지
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• 제14권4호
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• pp.504-516
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• 2011

In this paper, we will present a method to detect human hand and recognize hand gesture. For detecting the hand region, we use the feature of human skin color and hand feature (with boundary complexity) to detect the hand region from the input image; and use algorithm of optical flow to track the hand movement. Hand gesture recognition is composed of two parts: 1. Posture recognition and 2. Motion recognition, for describing the hand posture feature, we employ the Fourier descriptor method because it's rotation invariant. And we employ PCA method to extract the feature among gesture frames sequences. The HMM method will finally be used to recognize these feature to make a final decision of a hand gesture. Through the experiment, we can see that our proposed method can achieve 99% recognition rate at environment with simple background and no face region together, and reduce to 89.5% at the environment with complex background and with face region. These results can illustrate that the proposed algorithm can be applied as a production.