• 한국통신학회:학술대회논문집
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• 한국통신학회 1984년도 추계학술발표회논문집
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• pp.98-100
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• 1984

This paper design the emulator of the 8 bit microprocessor based on the z-80. The system control the debugging relation ship concerning the hardware and the software between the target system and the host system. It is purpose that emulator manufacture low cost.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4682-4705
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• 2020

The Unmanned Aerial Vehicles (UAV) networks consisting of low-cost UAVs are very vulnerable to smart jammers that can choose their jamming policies based on the ongoing communication policies accordingly. In this article, we propose a novel cloud and edge-aided mobile communication scheme for low-cost UAV network against smart jamming. The challenge of this problem is to design a communication scheme that not only meets the requirements of defending against smart jamming attack, but also can be deployed on low-cost UAV platforms. In addition, related studies neglect the problem of decision-making algorithm failure caused by intermittent ground-to-air communication. In this scheme, we use the policy network deployed on the cloud and edge servers to generate an emergency policy tables, and regularly update the generated policy table to the UAVs to solve the decision-making problem when communications are interrupted. In the operation of this communication scheme, UAVs need to offload massive computing tasks to the cloud or the edge servers. In order to prevent these computing tasks from being offloaded to a single computing resource, we deployed a lightweight game algorithm to ensure that the three types of computing resources, namely local, edge and cloud, can maximize their effectiveness. The simulation results show that our communication scheme has only a small decrease in the SINR of UAVs network in the case of momentary communication interruption, and the SINR performance of our algorithm is higher than that of the original Q-learning algorithm.

• Transactions on Electrical and Electronic Materials
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• 제15권2호
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• pp.91-95
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• 2014

This paper presents the structure and process technology of simple and low-cost wafer-level packaging (WLP) for thin film radio frequency (RF) devices. Low-cost practical micromachining processes were proposed as an alternative to high-cost processes, such as silicon deep reactive ion etching (DRIE) or electro-plating, in order to reduce the fabrication cost. Gold (Au)/Tin (Sn) alloy was utilized as the solder material for bonding and hermetic sealing. The small size fabricated WLP of $1.04{\times}1.04{\times}0.4mm^3$ had an average shear strength of 10.425 $kg/mm^2$, and the leakage rate of all chips was lower than $1.2{\times}10^{-5}$ atm.cc/sec. These results met Military Standards 883F (MIL-STD-883F). As the newly proposed WLP structure is simple, and its process technology is inexpensive, the fabricated WLP is a good candidate for thin film type RF devices.

• 전기학회논문지
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• 제63권9호
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• pp.1259-1265
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• 2014

In this paper, the real-time attitude determination based Matlab using low-cost receivers was designed and evaluated. The GNSS attitude determination system was implemented to operation in real-time by TimerCallback in MATLAB. The TTM(Transmission Time Misalignment) of U-blox receiver was confirmed through zero baseline tests and this problem was revised. The computed attitude by the high-cost NovAtel receiver was compared to the computed attitude by the low-cost U-blox receiver. As a result of this, the performance of attitude determination systems by low-cost receiver was confirmed. To determine baseline, LAMBDA and BC-LAMBDA for integer ambiguities search methods were used. To confirm suitable integer ambiguity search method in real-time attitude determination algorithm, determined baselines by two methods were compared, and it was confirmed that BC-LAMBDA is more suitable. As a result of this, the operation of real-time attitude determination system was confirmed using 3 low-cost receivers.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.1-10
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• 2021

The Internet of things (IoT) is the main advancement in data processing and communication technologies. In IoT, intelligent devices play an exciting role in wireless communication. Although, sensor nodes are low-cost devices for communication and data gathering. However, sensor nodes are more vulnerable to different security threats because these nodes have continuous access to the internet. Therefore, the multiparty security credential-based key generation mechanism provides effective security against several attacks. The key generation-based methods are implemented at sensor nodes, edge nodes, and also at server nodes for secure communication. The main challenging issue in a collaborative key generation scheme is the extensive multiplication. When the number of parties increased the multiplications are more complex. Thus, the computational cost of batch key and multiparty key-based schemes is high. This paper presents a Secure Multipart Key Distribution scheme (SMKD) that provides secure communication among the nodes by generating a multiparty secure key for communication. In this paper, we provide node authentication and session key generation mechanism among mobile nodes, head nodes, and trusted servers. We analyzed the achievements of the SMKD scheme against SPPDA, PPDAS, and PFDA schemes. Thus, the simulation environment is established by employing an NS 2. Simulation results prove that the performance of SMKD is better in terms of communication cost, computational cost, and energy consumption.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.475-480
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• 2018

In OFDM-based systems, FFT is a critical component since it occupies large area and consumes more power. In this paper, we present a low hardware-cost and low power 512-point pipelined FFT design method for OFDM applications. To reduce the number of twiddle factors and to choose simple design architecture, the radix-$2^4-2^3$ algorithm are exploited. For twiddle factor multiplication, we propose a new canonical signed digit (CSD) complex multiplier design method to minimize the hardware-cost. In hardware implementation with Intel FPGA, the proposed FFT design achieves more than about 28% reduction in gate count and 18% reduction in power consumption compared to the previous approaches.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 추계 종합학술대회 논문집
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• pp.280-284
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• 2004

안테나의 특성 중 지향성(Directivity)과 관계있는 방사 패턴을 측정하기 위한 저가의 근역장 측정 시스템을 설계한다. 근역장 측정방법은 평면주사법에 기반을 둔 개선된 원통형 주사법 공식을 이용한다. 고가의 측정 장비인 네트워크 분석기를 대체하기 위한 방법을 제시하고 필요한 장치 규격을 제안한다.

• 한국정보통신학회논문지
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• 제24권8호
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• pp.1109-1112
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• 2020

This paper presents a low cost hardware message passing engine of enhanced atomic pipelined broadcast based on processing node status. In this algorithm, the previous atomic pipelined broadcast algorithm is modified to reduce the waiting time until next broadcast communication. For this, the processor change the transmission order of processing nodes based on the nodes' communication channel. Also, the hardware message passing engine architecture of the proposed algorithm is modified to be adopted to multi-core processor. The synthesized logic area of the proposed hardware message passing engine was reduced by about 16%, compared by the pre-existing hardware message passing engine.

• 한국인터넷방송통신학회논문지
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• 제23권3호
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• pp.59-64
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• 2023

화재 재난방송 시스템에서는 아날로그, 디지털, 네트워크 디지털 전관 방송 시스템으로 나뉘며, 네트워크 디지털 전광 방송 시스템에서 중요한 사양은 낮은 대기 시간(Low-latency), 높은 샘플링 레이트, 다채널 입출력이다. 기존에 데이터링크 층의 MAC 주소 기반으로 구별하는 AoE(Audio over Ethernet) 방법을 널리 사용하고 있다. 그러나 이 방법은 복잡성과 비용이 증가하는 문제가 있다. 이에 본 제안은 AoIP(Audio over Internet Protocol)/UDP 방식으로 별도의 중복적인 네트워크가 필요 없이 IP(Internet Protocol) 주소로 손쉽게 구별하는 통신을 할 수 있어 네트워크를 자유롭게 사용 구성하고 복잡도를 낮추어 비용을 낮출 수 있도록 제안한다. AoIP/UDP 방식으로 구현 후 실험결과 2.66ms 대기 시간 성능으로 동등한 성능으로 비용의 개선함을 보였다.

• 대한전자공학회논문지TC
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• 제42권4호
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• pp.1-6
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• 2005

본 논문에서는 송신기와 수신기의 구현에 있어서 많은 장점을 제공하는 직접 확산-주파수(DSSS-FSK) 변조를 제안한다. 주파수 변조를 사용하여, 직접 확산 통신에서도 주파수합성기(PLL)를 이용한 송신기의 구현이 가능하므로 저전력, 저가격이 가능하다. 또한, 반송과 인접 대역에 정보를 전송하지 않아서 직접변환방식 수신기(DCR)의 구현을 용이하게 한다 한편, DSSS-FSK 신호를 위한 최적 동기 검파와 반동기 상관 검파 구조를 제안하고 그 성능을 분석한다. 매우 큰 반송파 주파수오프셋에서도 우수한 비트오율성능을 가지기 위해서, 분할 반동기 상관 검파 구조를 제안하고 성능을 분석한다.