• 대한전자공학회논문지TC
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• 제49권7호
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• pp.6-11
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• 2012

IEEE 802.16e는 수면 모드 작동기법을 사용하여 이동 단말기(Mobile Station: MS)의 제한된 에너지를 관리한다. MS는 수면 모드의 비가용 구간에 물리적인 작동 요소의 출력을 낮출 수 있다. 이 논문은 비가용 구간를 체계적으로 증가시켜 에너지 소모율을 감소시키기 위하여, MS에 I형과 II형의 활성화된 절전 클래스(PSC)가 존재할 때 강화된 절전 메커니즘(ePSM)을 제안한다. 성능 평가 결과, ePSM은 비가용 구간뿐 아니라 에너지 소비에 있어서도 기존 방식에 비해 성능을 향상시킨 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권4호
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• pp.1246-1262
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• 2021

Recent studies have demonstrated the strong ability of deep convolutional neural networks (CNNs) to significantly boost the performance in single image super-resolution (SISR). The key concern is how to efficiently recover and utilize diverse information frequencies across multiple network layers, which is crucial to satisfying super-resolution image reconstructions. Hence, previous work made great efforts to potently incorporate hierarchical frequencies through various sophisticated architectures. Nevertheless, economical SISR also requires a capable structure design to balance between restoration accuracy and computational complexity, which is still a challenge for existing techniques. In this paper, we tackle this problem by proposing a competent architecture called Enhanced U-Net Network (EUN), which can yield ready-to-use features in miscellaneous frequencies and combine them comprehensively. In particular, the proposed building block for EUN is enhanced from U-Net, which can extract abundant information via multiple skip concatenations. The network configuration allows the pipeline to propagate information from lower layers to higher ones. Meanwhile, the block itself is committed to growing quite deep in layers, which empowers different types of information to spring from a single block. Furthermore, due to its strong advantage in distilling effective information, promising results are guaranteed with comparatively fewer filters. Comprehensive experiments manifest our model can achieve favorable performance over that of state-of-the-art methods, especially in terms of computational efficiency.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1780-1785
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• 2015

In this paper, the adaptive particle swarm optimization (APSO) algorithm is employed to design a gain-enhanced antenna with a reflector for energy harvesting. We placed the reflector below the main radiating element. Its back-radiated field is reflected and added to the forward radiated field, which could increase the antenna gain. We adopt the adaptive particle swarm optimization (APSO) algorithm, which improves the speed of convergence with a high frequency solver. The result shows that performance of the optimized design successfully satisfied the design goal of the frequency band, gain and axial ratio.

• 유통과학연구
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• 제12권10호
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• pp.29-35
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• 2014

Purpose - This study highlights the inter-dependence between business and society. Various business strategies like Corporate Philanthropy and CSR (Corporate Social Responsibility) are introduced to establish better relationship between business and society. Research Design, Data, and Methodology - This study presents a research model clarifying the role of Creating Shared Value (CSV) and its influence on overall corporate performance. Further, we reveal the mediating role of corporate trust generated by various mechanisms of economic and social values, leading to enhanced corporate performance. Results - The proposed research model addresses five different proposals indicating that, by incorporating CSV approaches, organizations can create both business and social values. These values help positively influence corporate trust, ultimately facilitating improvements in overall corporate performance. Conclusions - CSV is currently in its early stage; it is difficult to gather meaningful data to measure its performance. However, this study seeks to connect CSV with other important factors such as corporate trust. The proposed model can be a starting point for a more empirical and formal conceptualization of CSV along with other important links.

• 한국ITS학회 논문지
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• 제10권1호
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• pp.60-66
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• 2011

정보통신과 네트워크 기술의 발달로 교통의 효율성과 교통이용자의 안전성을 높이는 지능형교통시스템(ITS) 서비스가 다양하게 제공되고 있다. 이동하는 자동차에 ITS 서비스를 제공하기 위하여 DSRC, Wibro, HSPA, WAVE 등 다양한 통신 방식이 이용되고 있지만, 각 통신방식의 규격과 성능의 차이로 모든 서비스를 하나의 통신방식으로 이용하기에는 어려움이 많다. 본 논문은 끊임없는 ITS 서비스 제공을 위하여 다양한 통신방식을 번갈아 이용하는 시스템을 제안하였으며, 임베디드플랫폼 기반의 단말기에서 성능을 구현하였다.

• Journal of Positioning, Navigation, and Timing
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• 제4권2호
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• pp.79-85
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• 2015

Existing Differential GPS (DGPS) pseudorange correction (PRC) generation techniques based on a virtual reference station cannot effectively assign a weighting factor if the baseline distance between a user and a reference station is not long enough. In this study, a virtual reference station DGPS PRC generation technique was developed based on an enhanced inverse distance weighting method using an exponential function that can maximize a small baseline distance difference due to the dense arrangement of DGPS reference stations in South Korea, and its positioning performance was validated. For the performance verification, the performance of the model developed in this study (EIDW) was compared with those of typical inverse distance weighting (IDW), first- and second-order multiple linear regression analyses (Planar 1 and 2), the model of Abousalem (1996) (Ab_EXP), and the model of Kim (2013) (Kim_EXP). The model developed in the present study had a horizontal accuracy of 53 cm, and the positioning based on the second-order multiple linear regression analysis that showed the highest positioning accuracy among the existing models had a horizontal accuracy of 51 cm, indicating that they have similar levels of performance. Also, when positioning was performed using five reference stations, the horizontal accuracy of the developed model improved by 8 ~ 42% compared to those of the existing models. In particular, the bias was improved by up to 27 cm.

• 디지털산업정보학회논문지
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• 제11권3호
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• pp.45-51
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• 2015

In this paper, we discuss the belief propagation decoding algorithm for polar codes. The performance of Polar codes for shorter lengths is not satisfactory. Motivated by this, we propose a novel technique to improve its performance at short lengths. We showed that the probability of messages passed along the factor graph of polar codes, can be increased by multiplying the current message of nodes with their previous message. This is like a feedback path in which the present signal is updated by multiplying with its previous signal. Thus the experimental results show that performance of belief propagation polar decoder can be improved using this proposed technique. Simulation results in binary-input additive white Gaussian noise channel (BI-AWGNC) show that the proposed belief propagation polar decoder can provide significant gain of 2 dB over the original belief propagation polar decoder with code rate 0.5 and code length 128 at the bit error rate (BER) of $10^{-4}$.

• Korea-Australia Rheology Journal
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• 제18권1호
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• pp.25-30
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• 2006

To enhance the stability of dispersed polyaniline (PANI) particles in a silicone oil system, a nonionic surfactant was adopted, and its effect on the electrorheological (ER) performance was investigated under an applied electric field. In the presence of a nonionic surfactant, the PANI based ER fluid exhibited not only an improved sedimentation stability based on the estimated sedimentation ratio but also an enhanced maximum yield stress behavior. Furthermore, the surfactant added ER suspension was applied to an ER damper system, and its damping performance was compared with the ER suspension without a surfactant.

• 한국유체기계학회 논문집
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• 제19권4호
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• pp.43-47
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• 2016

Vertical axis wind turbine, despite of its limit in power efficiency, the simplicity in structure and maintenance is a competitive factor that keeps this type of turbine in the game until nowadays. Continuous solutions have been given to handle its major weakness and the use of omni-directional guide vane is an considerable one. In this paper, a 5kkW scale Savonius-based wind turbine enhanced with such guide vane system was design and studied. Together with reasonable blade design, the wind turbine shows promising performance compared with basic design while maintaining its original advantages.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권4호
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• pp.1337-1358
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• 2015

In this paper, we present an analytical and simulated study on the performance of adaptive vehicular ad hoc networks (VANET) priority based on Transmission Distance Reliability Range (TDRR) and data type. VANET topology changes rapidly due to its inherent nature of high mobility nodes and unpredictable environments. Therefore, nodes in VANET must be able to adapt to the ever changing environment and optimize parameters to enhance performance. However, there is a lack of adaptability in the current VANET scheme. Existing VANET IEEE802.11p's Enhanced Distributed Channel Access; EDCA assigns priority solely based on data type. In this paper, we propose a new priority scheme which utilizes Markov model to perform TDRR prediction and assign priorities based on the proposed Markov TDRR Prediction with Enhanced Priority VANET Scheme (MarPVS). Subsequently, we performed an analytical study on MarPVS performance modeling. In particular, considering five different priority levels defined in MarPVS, we derived the probability of successful transmission, the number of low priority messages in back off process and concurrent low priority transmission. Finally, the results are used to derive the average transmission delay for data types defined in MarPVS. Numerical results are provided along with simulation results which confirm the accuracy of the proposed analysis. Simulation results demonstrate that the proposed MarPVS results in lower transmission latency and higher packet success rate in comparison with the default IEEE802.11p scheme and greedy scheduler scheme.