• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2006년도 춘계학술발표대회
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• pp.1041-1044
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• 2006

This paper proposes a dynamic IP address configuration (DAC) scheme for mSCTP handover, which exploits the information from the link layer to support SCTP handover between heterogeneous access networks. The proposed DAC scheme enables a mobile terminal to automatically add a new IP address in the newly visited region, change the primary path, and delete the old IP address so as to support the mSCTP handover. For experimental analysis of mSCTP handover, we consider the handover scenarios for 3G-BWA and 3G-WLAN over Linux platforms. From experimental results, it is shown that the throughput and handover latency of the mSCTP handover would be affected by the timing of primary-change and the overlapping period.

• Journal of Multimedia Information System
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• 제3권4호
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• pp.141-148
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• 2016

This paper proposes a medium access control (MAC) protocol for multiple-input multiple-output (MIMO) ad-hoc networks. Multiple-packet receptions in MIMO systems have attracted as a key technique to achieve a high transmission rate. In the conventional protocols for multiple-packet receptions, timing offsets among multiple-frame transmissions cause frame collisions induced by hidden nodes, which degrades network performance. In the proposed protocol, transmission synchronization among hidden nodes can be achieved by applying pulse/tone exchanges. By applying the pulse/tone exchanges, multiple-packet receptions among hidden nodes can be achieved, which enhances network throughputs compared with the conventional protocol. Simulation results show effectiveness of the proposed protocol.

• Journal of Communications and Networks
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• 제2권1호
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• pp.69-75
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• 2000

A new frame synchronization confirmation technique using a pilot pattern of both uplink and downlink channels is proposed for W-CDMA (Wideband Code Division Multiple Access) system. It is shown that by using this technique, we can cancel the side lobe for autocorrelation functions of the frame synchronization words of pilot pattern have the maximum to-of-phase autocorrelation value "4" with two peak values equal in magnitude and opposite in polarity at zero and middle shifts. Due to this side lobe cancellation effect, therefore, the autocorrelation function of the frame synchronization words becomes ideal for the frame synchronization confirmation since double maximum correlation values equal in magnitude and opposite polarity at zero ad middle shifts can be achieved. This property can be used to double check frame synchronization timing and thus. improve the frame synchronization confirmation performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.239-240
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• 2008

A new frequency offset estimator using low cross-property of PN sequences is proposed in the orthogonal frequency division multiple access (OFDMA) uplink systems. Simulation results show that the proposed estimator improves the mean square error (MSE) performance compared to conventional estimator [2] where each user have both different timing offset and different frequency offset. In addition, the MSE performance is improved as the length of PN sequence increases.

• 음성과학
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• 제10권3호
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• pp.89-101
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• 2003

This paper investigates edge effects on the relationship between the underlying tonal sequence and its surface realization in the IP-final Accentual Phrase within the Optimality Theoretic framework. I will examine the way in which AP tones are aligned with their associated syllables in IP-final position. In Korean. Jun's (1996) 'see-saw effect' does not allow any two identical tones if they are marking a boundary of a prosodic group. A phonetic experiment conducted in this paper suggests that the 'see-saw effect' only apply to H boundary tones. Furthermore, it will be shown that the timing of tonal peaks is determined through the ranking of a set of violable constraints. The AP tonal realization is achieved through the access to the global intonation in a complicated way. In the course of discussion, pitch patterns in IP-medial Accentual Phrase will also be discussed.

• 전자공학회논문지C
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• 제34C권12호
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• pp.9-19
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• 1997

This paper describes the design and FPGA implementation of a system control unit within a multiprocessor chip which can be used as a node processor ina massively parallel processing (MPP) caches, memory management units, a bus unit and a system control unit. Major functions of the system control unit are locking/unlocking of the shared variables of protected access, synchronization of instruction execution among four integer untis, control of interrupts, generation control of processor's status, etc. The system control unit was modeled in very high level using verilog HDL. Then, it was simulated and verified in an environment where trap handler and external interrupt controller were added. Functional blocks of the system control unit were changed into RTL(register transfer level) model and synthesized using xilinx FPGA cell library in synopsys tool. The synthesized system control unit was implemented by Xilinx FPGA chip (XC4025EPG299) after timing verification.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권8호
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• pp.492-499
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• 2003

This paper presents the analysis and the implementation of the asynchronous communication portion of the IEEE 802.11 MAC protocol. We have used PRISM2 chipsets from INTERSIL to build baseband, IF, and RF parts and PCI controller from PLX to interface LLC Layer. We have implemented DCF(Distributed Coordination Function) service using CSMA/CA(Carrier Sense Multiple Access with Collision Acoidance) with backoff algorithm and RTS/CTS protocol. Also, we have implemented TSF(Timing Synchronization Function) which can be used for power management frequency hop synchronization, and other management function. This study can be used as a reference for the MAC protocol implementation and MAC controller design in very high speed wireless LAN which complies with the IEEE 802.11 standard.

• 대한임베디드공학회논문지
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• 제14권5호
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• pp.227-237
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• 2019

Ultra-low latency control is one of the characteristics of 5G cellular network services, which means that the control loop is handled in milliseconds. To achieve this, it is necessary to identify time delay factors that occur in all components related to CPS control loop, including new 5G cellular network elements such as MEC, and to optimize CPS control loop in real time. In this paper, a novel CPS architecture for ultra-low latency control of CPS is designed. We first define the ultra-low latency characteristics of CPS and the CPS concept model, and then propose the design of the control loop performance monitor (CLPM) to manage the timing information of CPS control loop. Finally, a case study of MEC-based implementation of ultra-low latency CPS reviews the feasibility of future applications.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.174-179
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• 2017

We designed the CMOS analog integrate and fire (I&F) neuron circuit for driving memristor based on resistive-switching random access memory (RRAM). And we fabricated the RRAM device that have $HfO_2$ switching layer using atomic layer deposition (ALD). The RRAM device has gradual set and reset characteristics. By spice modeling of the synaptic device, we performed circuit simulation of synaptic device and CMOS neuron circuit. The neuron circuit consists of a current mirror for spatial integration, a capacitor for temporal integration, two inverters for pulse generation, a refractory part, and finally a feedback part for learning of the RRAM. We emulated the spike-timing-dependent-plasticity (STDP) characteristic that is performed automatically by pre-synaptic pulse and feedback signal of the neuron circuit. By STDP characteristics, the synaptic weight, conductance of the RRAM, is changed without additional control circuit.

• 한국정보통신학회논문지
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• 제9권6호
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• pp.1167-1173
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• 2005

본 논문에서는 DS-CDMA 신호들의 코드 타이밍을 획득하기 위하여 안테나 어레이의 이용에 관한 내용을 다루고자 한다. 다중 사용자 환경의 시변 Rayleigh 페이딩 채널 하에서 다중의 고정 빔들을 기존의 MUSIC 동기 획득 방법에 적용함으로서 동기 획득 확률들을 평가한다. 전 방위각 영역을 공간 필터링을 위해서 안테나의 수만큼 나누어서 각각의 고정 빔이 각 방위각 구역을 맡도록 한다. 간섭 신호 억제 능력을 가진 고정 빔들은 부가적인 자유도를 제공한다. 그리하여 단 하나의 안테나를 사용하는 기존의 MUSIC 알고리즘보다 더 많은 사용자들의 동기 획득을 위해서 다중 빔 기반의 MUSIC 추정기를 사용할 수 있도록 한다. 이러한 다중 빔 기반의 부분공간 접근 방법을 다중 사용자 시나리오에서 단 하나의 안테나를 사용하는 MUSIC 기법의 성능을 상당히 개선할 수 있음을 검증하기 위해서 시뮬레이션을 수행한다.