• Journal of the Korea Society of Computer and Information
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• v.20 no.7
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• pp.49-56
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• 2015

In this paper, we introduce recent cloud system security technologies categorizing them according to Reliability, Availability, Serviceability, Integrity, and Security (RASIS), terms that evaluate robustness of the computer system. Then we describe examples of security attacks and corresponding security technologies for each of them. We introduce security technologies based on Software Defined Network (SDN) for Reliability, security technologies based on hypervisor and virtualization for Availability, disaster restoration systems for Serviceability, authorization and access control technologies for Integrity, and encryption algorithms for Security. We believe that this paper provide wise view and necessary information for recent cloud system security technologies.

• ETRI Journal
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• v.40 no.5
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• pp.643-652
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• 2018

Dysarthria is a degenerative disorder of the central nervous system that affects the control of articulation and pitch; therefore, it affects the uniqueness of sound produced by the speaker. Hence, dysarthric speaker recognition is a challenging task. In this paper, a feature-extraction method based on deep belief networks is presented for the task of identifying a speaker suffering from dysarthria. The effectiveness of the proposed method is demonstrated and compared with well-known Mel-frequency cepstral coefficient features. For classification purposes, the use of a multi-layer perceptron neural network is proposed with two structures. Our evaluations using the universal access speech database produced promising results and outperformed other baseline methods. In addition, speaker identification under both text-dependent and text-independent conditions are explored. The highest accuracy achieved using the proposed system is 97.3%.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1021-1023
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• 2012

본 논문에서는 UWB 기술 기반 WiMedia Distributed Medium Access Control (D-MAC) 표준 프로토콜에 적용할 수 있는 Satisfaction of QoS (SoQ) 기반 협력 통신 프로토콜을 제안한다. 이를 위해 UWB 링크 전송 속도와 QoS 척도에 따른 릴레이 노드 선정 알고리즘을 제안한다. 본 논문에서 제안하는 SoQ 기반 협력 통신 프로토콜은 분산적인 D-MAC 표준 기술과 호환성을 갖고, 각 디바이스에서 독립적으로 실행되는 SoQ 기반 Relay Node Selection (RNS) 기준에 따라 실행된다.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.299-310
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• 2016

In this paper, we perform analysis of the performance of low-power communication technology, IEEE 802.15.4 MAC (Media Access Control) protocol used in internet of things. Wide variety of devices in internet of things generate different kinds of traffic characteristics and heterogeneous traffic environment is therefore considered in contrast to existing works. With the help of the Markov chain the performance of the protocol is derived as a function of the MAC parameters and based on the results a framework to determine energy-efficient optimal MAC parameters for applications in real time is proposed. Proposed method is shown to be more efficient in terms of energy consumption through performance comparison over application scenarios compared to operation with fixing MAC parameters, and its practicability on small devices with limited computing power is verified through evaluating the accuracy and speed of the proposed framework.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.83-90
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• 2016

In this paper, we performed the analysis of transmission performance for Collision Free Period(CFP) supported by the low-power communication technology, IEEE 802.15.4 MAC (Media Access Control). For the analysis, periodic traffic, original service target of CFP, is considered and, according to the Quality of Service required, packet arrival pattern to MAC layer is categorized as batch and non-batch, and analysis on throughput, delay, and energy is performed for those patterns. On the basis of the obtained analysis, performance comparison with Collision Avoidance Period(CAP) is carried out for the health care applications that generate periodic traffic such as Pedometer, ECG, EMG. The evaluation confirms that CFP is more energy efficient for healthcare applications that generate periodic and time-critical traffic and moreover for the application with high bandwidth requirement CFP achieves up to 46% energy savings compared to CAP.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.85-96
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• 2008

Neighbor Discovery(ND) protocol is used to exchange an information of the neighboring nodes on the same link in the IPv6 protocol environment. For protecting the ND protocol, firstly utilizing Authentication Header(AH) of the IPsec protocol was proposed. But the method has some problems-uses of key exchange protocol is not available and it is hard to distribute manual keys. And then secondly the SEcure Neighbor Discovery(SEND) protocol which protects all of the ND message with digital signature was proposed. However, the digital signature technology on the basis of public key cryptography system is commonly known as requiring high cost, therefore it is expected that there is performance degradation in terms of the availability. In the paper, to improve performance of the SEND protocol, we proposed a modified CGA(Cryptographically Generated Address) which is made by additionally adding MAC(Media Access Control) address to the input of the hash function. Also, we proposed cache mechanism. We compared performance of the methods by experimentation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.59-63
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• 2022

In recent years, research on smart factory wireless mobile communication technology that wirelessly remotely controls utilities is being actively conducted. The Wi-SUN(Wireless Smart Utility Network) Alliance proposed Wi-SUN protocol structure suitable for building a platform such as a smart factory as a new wireless communication standardization standard based on EEE802.15.4g/e. It analyzes the performance of the IEEE802.15.4e CSL(Coordinated Sampled Listening) Mode MAC(Media Access Control) in terms of power consumption and looks at considerations for efficient operation. Although CSL-MAC can dramatically reduce power consumption at the receiving end in an asynchronous manner, it has been found that the transmitting end has a disadvantage in that power consumption occurs due to an excessive wake-up sequence.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.65-70
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• 2024

In recent years, research on smart factory wireless mobile communication technology that wirelessly remotely controls utilities is being actively conducted. The Wi-SUN (Wireless Smart Utility Network) Alliance proposed a Wi-SUN protocol structure suitable for building a platform such as a smart factory as a new wireless communication standardization standard based on EEE802.15.4g/e. It analyzes the performance of the IEEE802.15.4e Receiver Initiated Transmission(RIT) Mode Media Access Control (MAC) in terms of throughput and latency, and looks at considerations for efficient operation. RIT mode shows that as the check interval becomes longer, delay time and throughput decrease. It was shown that as the traffic load increases, if the RIT check interval is shortened, the delay time can be shortened and throughput can be increased. RIT mode has the advantage of low power consumption and has neutral characteristics between IEEE802.15.4 and CSL mode in terms of delay time and throughput.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.237-239
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• 2004

Wireless LAN Voice over IP(VoIP) equipment needs Quality-of-Service(QoS) with priority for processing real-time traffic. This paper shows transmit function implementation of wireless LAN(WLANs) media access control(MAC) support VoIP, and it has an advantage of guarantee of QoS and is adaptable to VoIP or mobile wireless equipment. The IEEE 802.11e standard in progress has four queues according to four access categories(AC) for transmit and the MAC transmits the data based on EDCA. The value of AC is from AC0 to AC3 and AC3 has the highest priority. The transmit method implemented at this paper ensure QoS using one transmit FIFO in hardware since real-time traffic data and non real-time traffic data has the different priority. The device driver classifies real-time data and non real-time data and transmit data to hardware with information about data type. The hardware conducts shorter backoff and selects faster AIFS slot for real-time data than it for non real-time data. Therefor It make give the real-time traffic data faster channel access chance than non real-time data and enhances QoS.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.2
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• pp.63-71
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• 2013

WAVE(Wireless Access for Vehicular Environment) System is a communication technology to monitor system failure and vehicle functions and management services to prevent possible incidents of driving a vehicle. In this paper, we have designed and implemented the mutual message processing through parameter between WME management module that manages WAVE system and MLME that manages the upper layer MAC(Media Access Control) module. Also, in order to verify the validity, we have carried out experiments to compare the speed of data processing by dividing data of 1Mbyte, 2Mbyte, 3Mbyte into the packets of 2KByte and 4KByte. Experiments data processing speed of 2KByte packet were shown about 173.62ms in 1MByte, 2MByte about 352.61ms, 3MByte about 550.13ms and, data processing speed of 4KByte packet, 1MByte approximately 87.56ms, 2MByte about 177.94ms, 3MByte about 277.18ms. Therefore, in WAVE system, the mutual messages processing through the parameters between WME and MLME module can be utilized in the various service of ITS(Intelligent Transportation Systems) depending on the speed of data processing.