• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.279-287
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• 1993

In this paper, double laxity threshold MLT(Minimum Laxity Threshold) algorithm and double queue threshold QLT(Queue Length Threshold) algorithm are proposed as DPS(Dynamic Priority Scheduling) techniques for advanced processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed by a computer simulation. According to the simulation results, it can be shown that the proposed double laxity threshold ML T algorithm advances the processing performance versus ML T algorithm for 2 or more classes delay sensitive traffics, and that double queue length threshold QL T algorithm provides more efficient performance than QL T for 2 or more classes of non real time traffics.

• Journal of Convergence Society for SMB
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• v.5 no.4
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• pp.37-42
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• 2015

Due to the advance of ICT, a variety of attacks have been developing and active. Recently, APT attacks using malicious codes have frequently occurred. Advanced Persistent Threat means that a hacker makes different security threats to attack a certain network of a company or an organization. Exploiting malicious codes or weaknesses, the hacker occupies an insider's PC of the company or the organization and accesses a server or a database through the PC to collect secrets or to destroy them. The paper suggested a countermeasure to cope with APT attacks through an APT attack process. It sought a countermeasure to delay the time to attack taken by the hacker and suggested the countermeasure able to detect and remove APT attacks.

• Journal of Convergence Society for SMB
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• v.5 no.1
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• pp.25-30
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• 2015

The APT attacks are hackers created a variety of security threats will continue to attack applied to the network of a particular company or organization. It referred to as intelligent sustained attack. After securing your PC after a particular organization's internal staff access to internal server or database through the PC or remove and destroy the confidential information. The APT attack is so large, there are two zero-day attacks and rootkits. APT is a process of penetration attack, search, acquisition, and is divided into outlet Step 4. It was defined in two ways how you can respond to APT through the process. Technical descriptions were divided into ways to delay the attacker's malicious code attacks time and plan for attacks to be detected and removed through.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.2
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• pp.93-100
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• 2009

As the Internet Protocol be widely/rapidly used in packet communication, common carriers are providing the multimedia service(Both direction real-time voice, video conference, remote educational etc.)on the Internet. Also the 070 VoIP (Voice over IP) service is provided by the carriers on the packer network. In order to offer VoIP service in Korea, common carrier has to acquire the optimum level for QoS(quality of service). In this paper, we study on CODEC quality to get a higher QoS for VoIP.

• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.239-249
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• 2011

In this paper, we propose a reliable $8{\times}8$ up-down switching polar relay code based on 3GPP LTE standard, motivated by 3GPP LTE down link, which is 30 bps/Hz for $8{\times}8$ MIMO antennas, and by Arikan's channel polarization for the frequency selective fading (FSF) channels with the generator matrix $Q_8$. In this scheme, a polar encoder and OFDM modulator are implemented sequentially at both the source node and relay nodes, the time reversion and complex conjugation operations are separately implemented at each relay node, and the successive interference cancellation (SIC) decoder, together with the cyclic prefix (CP) removal, is performed at the destination node. Use of the scheme shows that decoding at the relay without any delay is not required, which results in a lower complexity. The numerical result shows that the system coded by polar codes has better performance than currently used designs.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.213-219
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• 2011

Simulative target generators are needed for testing and calibrating various radar systems. The generator in this study discriminates the transmitting frequency from a radar and simulates parameters like target range, range rate, and atmospheric attenuation using the digital RF memory technique. The simulative target echo is then sent to the radar for testing and evaluation. This paper proposes a novel architecture for controlling the digital RF memory so it continually writes ADC data to the memory and reads it for the DAC with increasing one step address in order to control the delay of target range in a simple way. The target echo is programmed according to various preprogrammed scenarios and is generated in real time using a wireless local area network (LAN). To analyze the detected and generated target information easily, the system times for the radar and simulative target generator are synchronized using a global positioning system (GPS).

• IE interfaces
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• v.9 no.3
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• pp.180-193
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• 1996

본 논문에서는 시뮬레이션 모델을 통해 호유형뿐만 아니라 개인통신서비스에서 필수적인 핸드오버 및 위치등록 등의 모든 트래픽 유형을 고래했을 때 개인통신교환기(PCX : Personal Commuincations Exchange)에서의 지연시간을 분석하며, 지연시간에 대한 결과와 프로세서의 이용율로부터 개인통신교환기의 호처리 및 이동성처리용량을 분석하고 그에 따른 가입자의 수용능력을 추정한다. IPC(Inter-Processor Communications) 메시지의 송수신시간 및 메시지의 처리시간등 교환기 제어계의 성능분석에 필요한 입력 파라미터 값은 기존 ISDN(Integrated Services Digital Network) 및 CMS-MX(CDMA Mobile System-Mobile Exchange) 교환기의 측정자료를 이용하였다. 시뮬레이션 분석결과 PCX 교환기의 호처리 성능은 주로 번호번역 기능을 담당하는 프로세서인 NTP(Number Translation Processor)의 용량에 의해 결정되며, 가입자 밀도가 1,500명$/km^2$인 경우 호처리용량은 약 42만 BHC(Busy Hour Call Completion)로 추정되었고, 이에 상응하는 핸드오버 및 위치등록 처리용량은 각각 시간당 약 2만 6천히 및 40만 6천회로 나타났다. 이것은 가입자당 호처리 부하가 1.6BHC일 경우, 약 15만 7천 가입자를 수용할 수 있는 용량에 해당한다.

• ETRI Journal
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• v.36 no.4
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• pp.554-563
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• 2014

The burgeoning growth of real-time applications, such as interactive video and VoIP, places a heavy demand for a high data rate and guarantee of QoS from a network. This is being addressed by fourth generation networks such as Long-Term Evolution (LTE). But, the mobility of user equipment that needs to be handed over to a new evolved node base-station (eNB) while maintaining connectivity with high data rates poses a significant challenge that needs to be addressed. Handover (HO) normally takes place at cell borders, which normally suffers high interference. This inter-cell interference (ICI) can affect HO procedures, as well as reduce throughput. In this paper, soft frequency reuse (SFR) and multiple preparations (MP), so-called SFRAMP, are proposed to provide a seamless and fast handover with high throughput by keeping the ICI low. Simulation results using LTE-Sim show that the outage probability and delay are reduced by 24.4% and 11.9%, respectively, over the hard handover method - quite a significant result.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.42-52
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• 2006

The interest for IPv6, Which is next generation IP, increases, while th difficulty for adopting it into IT indestries also increase too. We also expect that Internet technologies develop 0 basis of All-IP networks, which include various heterogeneous networks. Therefore, it is necessary for network to support mobility and multicast capavility to create application with wide-variety- In this paper, we propose a scheme that be able to provide mobility and multicast efficient in IPv6 networks. The proposed scheme has been implemented and experimented on NS-2 and validated with respect to multicast packet delay time and count of Joining and pruning)

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.181-187
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• 2003

In high speed packet switching network, packet service by priority scheme prefer to QoS. Efficient packet service according to the priority scheme in high speed packet switch is a key point. Therefore development of priority service algorithm in the packet switch is very important. In this paper, we proposed W-iSLIP algorithm that service time take queue length into consideration and compared the proposed W-iSLIP algorithm to other previous proposed algorithm through simulation. Simulation results show 2.6% performance elevation in average delay, and 34.6% performance elevation in priority service.