• ETRI Journal
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• 제38권6호
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• pp.1031-1041
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• 2016

This paper presents millimeter-wave (mmWave) propagation characteristics and channel model parameters including path loss, delay, and angular properties based on 28 GHz and 38 GHz field measurement data. We conducted measurement campaigns in both outdoor and indoor at the best potential hotspots. In particular, the model parameters are compared to sub-6 GHz parameters, and system design issues are considered for mmWave 5G Giga communications. For path loss modeling, we derived parameters for both the close-in free space model and the alpha-beta-gamma model. For multipath models, we extracted delay and angular dispersion characteristics including clustering results.

• ETRI Journal
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• 제43권2호
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• pp.344-356
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• 2021

CRAFT is a tweakable block cipher introduced in 2019 that aims to provide strong protection against differential fault analysis. In this paper, we show that CRAFT is vulnerable to side-channel cube attacks. We apply side-channel cube attacks to CRAFT with the Hamming weight leakage assumption. We found that the first half of the secret key can be recovered from the Hamming weight leakage after the first round. Next, using the recovered key bits, we continue our attack to recover the second half of the secret key. We show that the set of equations that are solvable varies depending on the value of the key bits. Our result shows that 99.90% of the key space can be fully recovered within a practical time.

• 한국실내디자인학회논문집
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• 제14권3호
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• pp.234-242
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• 2005

Interface is a medium or channel to communicate between human and things, while interaction is the manner of communication between them. Interaction design is designing experience of user through the interaction process for human, thing, system, and space. Richard Buchanan suggests four kinds of interaction: interface (person to thing interaction), transaction (person to person interaction), human interaction (human and environment interaction) and participation (human to cosmos interaction). With digital technology, architecture and space design have made various experiments at form, function, and content of space. Space evolves from a physical container to a stage to provide narrative and create new experience to users. Since understanding users, creating experience, efficient space design, content planning, and applicable technology are required for interaction design in space, multi-disciplinary research and cooperation is needed.

• 한국통신학회논문지
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• 제32권2A호
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• pp.195-202
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• 2007

A differential space-frequency block code - orthogonal frequency division multiplexing (SFBC-OFDM) scheme as a multiple-input multiple-output (MIMO) transmission technique for next-generation digital multimedia broadcasting (DMB) is proposed in this paper. A linear decoding method for differential SFBC, which performs comparably to the ML decoding method, is derived for the cases of two or four transmit antennas. A simple table lookup method is proposed to improve the efficiency of the encoding/decoding process of DSFBC for the case of non-constant modulus constellations. A DMB MIMO channel model, developed by extending the 3GPP MIMO model to fit DMB environments, is used to compare BER performances of differential space block code schemes for various channel environments. Simulation results show that the differential SFBC-16QAM scheme using either four transmit antennas with one receive antenna or two transmit antennas with two receive antennas achieves a performance gain of 12dB than that of the conventional DQPSK scheme, even with a data rate twice faster.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.41-45
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• 2007

Multi-input multi-output (MIMO) system can increase data rate, capacity and bit error rate (BER) performance compare to traditional single antenna system. However MIMO technique is pointed out the problem that has high complexity to design receiver. So a recent trend of research on the MIMO system pays more attention to simplified implementation of receiver structure. In this paper, we propose differential space time block code (STBC) for MIMO system with cyclic delay diversity (CDD). This structure can provide a very close performance to that of the conventional diversity scheme with maximum likelihood (ML) detection without channel estimation block while the receiver structure is highly simplified. Bit error rate (BER) performance of the proposed system is simulated for an AWGN channel by theoretical and simulated approaches. The results of this paper can be applicable to the 4G mobile multimedia communication systems.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.153-158
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• 2000

Flow visualization and PIV measurements were conducted to investigate the flow characteristics of multi-channel with inclination angle. The water flow seeded with tiny vegetable powder as tracers revealed details of flow field. The PIV measurement to acquire multi-point velocity data simulatneously was carried out at three space of plates for 5, 10, and 15mm with variation of inlet flow rates of $0.25m^3/h$ and <$0.5m^3/h.$ Experiment results show that space of plates acts a significant role in separating process.

• 한국항공우주학회지
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• 제35권12호
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• pp.1067-1074
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• 2007

예조건화 오일러 방정식의 수렴특성을 개선하기 위하여 밀도에 대한 온도의 미분항의 크기를 조절하는 온도예조건화 방법을 제시하고자 한다. 다양한 마하수의 원형 턱이 있는 이차원 관내 유동을 계산하였다. 온도예조건화에 맞는 새로운 Roe의 FDS 기법의 수치 소산항을 유도하여 사용하였다. 온도예조건화는 예조건화 오일러 방정식의 수렴 속도를 증가시키는 것으로 나타났다

• Journal of Astronomy and Space Sciences
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• 제12권1호
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• pp.54-65
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• 1995

We present a design study for a remote sensing camera system which can be operated in multi-channel mode simultaneously with several bandpass filters. The camera control electronics is based on the multiplexed driving concept, which can provide a variety of flexibility for system control parameters and its individual optimisation. The design can also be applied to any system with linear sensors or frame sensors according to its functional requirements. The system design parameters have been examined, including modification of driving waveforms for different types of sensors, waveforms for low-nosie readout circuit in analog chain, and synchronisation with other signal processing.

• 천문학회보
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• 제39권2호
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• pp.87.2-87.2
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• 2014

Symbiotic stars and quasars exhibit prominent $H{\alpha}$ emission lines often accompanied with broad wings. $H{\alpha}$ emission nebulae in these objects are proposed to be optically thick to resonance scattering. The transfer of $H{\alpha}$ line photons are further complicated by the existence of another scattering channel leading to re-emission of $Ly{\beta}$. In this work are develop a Monte Carlo code to simulate the transfer of $H{\alpha}$ line photons incorporating the scattering channel into $Ly{\beta}$. We show various line profiles of $H{\alpha}$ and $Ly{\beta}$ emergent from our model nebulae. It is shown that temperature is a critical parameter which controls the ratio of emergent $Ly{\beta}$ flux to that of $H{\alpha}$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.202-205
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• 2003

The performance of space-frequency trellis coded (SFTC) OFDM system is analyzed in frequency selective fading channel. Using a pairwise error probability upper bound expression, we design the code and interleaver that can maximize the diversity and coding gain. To alleviate the performance degradation due to the inter-antenna product terms, we propose a new SFTC scheme that employs non-overlapped interleaving for each antenna A new code is optimized for the non-overlapped interleaving and a practical sub-optimal decoding algorithm is proposed. It is shown that the proposed scheme can substantially improve the performance compared to the conventional scheme that employs identical interleaving for all antennas.