• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.148-158
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• 2008

This paper proposes an efficient signal to noise ratio (SNR) estimation algorithm and its hardware implementation for adaptive transmission system using M-ary modulation scheme. In this paper, we present the implementation results of the proposed algorithm for the second generation digital video broadcasting via satellite (DVB-S2) system, and the proposed algorithm can be tailored to the other communication systems using adaptive transmissions. We built a look-up table (LUT) using the theoretical background of the received signal distribution, and by using this LUT we need just two comparators and a counter for the hardware implementation. For this reason, the hardware of the proposed scheme produces accurate estimation results even with extremely low complexity. The simulation results investigated in this paper reveal that the proposed method can produce estimation results within the specified SNR range in the DVB-S2 system, and it requires a few hundreds of samples for average estimation error of about 1 dB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.57-63
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• 2003

Aluminum Stranded Conductors Steel Reinforced (ACSR) in overhead transmission lines have slowly degraded due to pollutants in the air for a long period of time, so in the 2000, a number of them has been exceeded over their forecasted useful life. Since most of them are faced with assessment their present conditions in regard to economical maintenance, in this paper, we have suggested a method in order to evaluate the current condition of aged conductors by using dominant parameters such as elapsed years, environment index, and conductor configuration. A diagnostic system for predicting the deterioration grades corresponding to the lifetime of aged conductors is described, which is designed as an Adaptive Neuro-fuzzy Inference System (ANFIS) based on knowledge and experiences of experts. Applying this diagnostic system to practical transmission lines in domestic, it is shown that the system can be effectively used as a guide to perform nondestructive diagnosis and economical operation for old ACSR conductors.

• Journal of Digital Contents Society
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• v.12 no.3
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• pp.355-360
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• 2011

In this paper, the performance of OFDM (Orthogonal Frequency Division Multiplexing) was assessed by using computer simulations performed using Matlab. We analyzed channel estimation algorithm for adaptive modulation techniques and effect of system using designed simulator in Multimedia wireless communication multipath fading channel environment. Also, we analyzed performance of adaptive OFDM systems that apply adaptive equalizer using guided result through BER. In result, in case of adaptive modulation OFDM systems that modulation mode changes according to channel state, we knew that adaptive modulation OFDM systems have gains of about 7dB performance than general system (BER=$10^{-1}$). Thus we know that adaptive OFDM propose systems is required for efficient transmission in the high speed Multimedia wireless communication channel environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.110-113
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• 2012

DDS middleware transmits data packets through unicast or multicast method for discovering endpoints on a distributed network and exchanging information between endpoints. Depending on the communicating situation between endpoints, the transmission method which is used to exchange packets is already defined by the standard protocol. However, the predefined usage of the transmission method has a problem that the middleware does not deal with increasing usage of the system resources properly when the configuration of endpoint is changed dynamically. To solve this problem, we propose the scheme of selecting the packet transmission method in an adaptive manner.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.716-720
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• 2006

In this paper, we designed and proposed new routing algorithm that can support a variety of vital-sign traffic characteristic and could be applicable to USN for telemedicine by using adaptive transmission power level and increase frequency of routing request message. In proposed routing algorithm, when an emergency vital-sign traffic is applied, we use large transmission power to reduce route query response time and make the priority order in route process. On the other hand, for non emergency vital-sign traffic, we use low transmission power and adaptive decrease frequency of routing request message. which is insensitive to delay. The proposed scheme should be better QoS performance in complex USN than conventional method, which is performed based on uniform transmission power level.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.500-507
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• 2018

A three-channel radio frequency (RF) monopulse receiver using a data signal with a maximum transmission rate of 274 Mbps was designed. A monopulse receiver using a broadband communication signal was designed to operate in the Ku band, and it consists of a down-conversion module and a signal-processing module. To satisfy the performance of the proposed RF monopulse receiver, a signal-processing function less than the reception sensitivity for each transmission rate according to the adaptive transmission rate is required. To minimize signal reception and mutual frequency interference of various bandwidths, two RF filters were applied. To verify the satisfaction of system requirements, an AWR Corp. simulation tool was used.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1798-1804
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• 2017

This paper presents an approach of the Gustafson-Kessel (GK) clustering algorithm's performance in fault identification on power transmission lines. The clustering algorithm is incorporated in a scheme that uses hybrid intelligent technique to combine artificial neural network and a fuzzy inference system, known as adaptive neuro-fuzzy inference system (ANFIS). The scheme is used to identify the type of fault that occurs on a power transmission line, either single line to ground, double line, double line to ground or three phase. The scheme is also capable an analyzing the fault location without information on line parameters. The range of error estimation is within 0.10 to 0.85 relative to five values of fault resistances. This paper also presents the performance of the GK clustering algorithm compared to fuzzy clustering means (FCM), which is particularly implemented in structuring a data. Results show that the GK algorithm may be implemented in fault identification on power system transmission and performs better than FCM.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.109-114
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• 2003

Wireless communication systems are inevitable for efficient underwater activities. Because of the poor propagation characteristics of light and electromagnetic waves, acoustic waves are generally used for the underwater wireless communication. Although there are many kinds of information type, visual images take an essential role especially for search and identification activities. For this reason, we developed an acoustic-based underwater image transmission system under a dual use technology project supported by MOCIE (Ministry of Commerce, Industry and Energy). For the application to complicated and time-varying underwater environments all-digital transmitter and receiver systems are investigated. Array acoustic transducers are used at the receiver, which have the center frequency of 32kHz and the bandwidth of 4kHz. To improve transmission speed and quality, various algorithms and systems are used. The system design techniques will be discussed in detail including image compression/ decompression system, adaptive beam- forming, fast RLS adaptive equalizer, ${\partial}/4$ QPSK (Quadrilateral Phase Shift Keying) modulator/demodulator, and convolution coding/ Viterbi. Decoding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.621-629
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• 2001

In this thesis a wireless data transmission system has been proposed and analysed that uses the multi-carrier technique with the adaptive modulation scheme. In general, the OFDM(Orthogonal Frequency Division Multiplexing) system is assigning a same amount of information to all sub-carriers in a wireless data transmission. In the proposed system, the different amount of information is assigned to each sub-carrier depending on the state of channel and the target probability of error of system. With the proposed scheme, the transmission rate can be maximized with the fixed power and the required power to transmit the information can be minimized with the target probability of error of system.

• IMMUNE NETWORK
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• v.14 no.4
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• pp.187-200
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• 2014

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, $CD4^+$ Th1 T cells producing IFN-${\gamma}$ are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.