• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.649-655
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• 2000

Real-time application programs have constraints which need to be met between media-data. These constraints represents the delay time ad quality of service between media-data to be presented. In order to efficiently describe the delay time and quality of service, a new synchronization mechanism is needed. Proposed paper is a dynamic synchronization that minimized the effects of adaptive transmission delay time. That is, the method meets the requirements of synchronization between media-dat by handling dynamically the adaptive waiting time resulted from variations of delay time. In addition, the mechanism has interval adjustment using maximum delay jitter time. This paper decreases the data loss resulted from variation of delay time and from loss time of media-data by means of applying delay jitter in order to deal with synchronization interval adjustment. Plus, the mechanism adaptively manages the waiting time of smoothing buffer, which leads to minimize the gap from the variation of delay time. The proposed paper is suitable to the system which requires the guarantee of high quality of service and mechanism improves quality of services such as decrease of loss rate, increase of playout rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.940-949
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• 1998

The paper proposes an effective mechanism hiring the adaptive buffer control schemes on the mobile seceiver's side that can resolve the problems of delay spikes caused by the handover process onthe cell boundaries when they transmit real-time moving images through the high speed wireless channels. to confirm the effectiveness of the proposed schemes, we have modeled the characteristics of the random errors on the wireless channels, the burst errors and that of the transmission delay by the handover. We also compared the rate of the delay-adaptation of the receive buffers caused by the delay and delay spikes. the comparison was done by testing the suggested schemes against the existing schemes by applying tehm to the packet delay model. We also could identify the noticable reduction of the casesof buffer delay and overflow compared with the conventional schemes, by applying the suggested algorithm to the video image compressed by H.263.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.175-183
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• 2008

QoS-support technology in networks is based on measuring QoS metrics which reflect a magnitude of stability and performance. The one-way delay measurement of the QoS metrics especially requires a guarantee of clock synchronization between end-to-end hosts. However, the hosts in networks have a relative or absolute difference in clock time by reason of clock offsets. flock skews and clock adjustments. In this paper, we present a theorem, methods and simulation results of one-way delay and clock offset estimations between end-to-end hosts. The proposed theorem is a relationship between one-way delay, one-way delay variation and round-trip time And we show that the estimation error is mathematically smaller than a quarter of round-trip time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2376-2385
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• 1994

In receiving the digital TV signal, both decoding delay and the channel hopping delay are very critical factors in applications. The intra-slice coding in the MPEG-2 SIMPLE PROFLE of No B-picture is one of the primary methods for short delay time in video decoding. It has the advantage of short decoding delay, but has the drawback of long channel hopping delay time. In this paper, we propose a method to reduce the channel delay with negligible loss in SNR performance. It is shown that dividing pictures into several regions of slices and adding some restriction in motion vector search for inter-frame coding. hence the random acess points are effectively increased. and the channel hopping delay is reduced.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.87-90
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• 2000

This paper describes a register-controlled symmetrical delay-locked-loop (DLL) using hybrid delay line for use in a high frequency double-data-rate DRAM. The proposed DLL uses a hybrid delay line which can cover two-step delays(coarse/fine delay) by one delay element. The DLL dissipate less power than a conventional dual-loop DLL which use a coarse and a fine delay element and control separately. Additionally, this DLL not only achieves small phase resolution compared to the conventional digital DLL's when it is locked but it also has a great simple delay line compared to a complex dual-loop DLL.

• Journal of electromagnetic engineering and science
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• v.15 no.2
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• pp.76-81
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• 2015

This paper presents a design of a transmission line negative group delay (NGD) circuit with multiple pole characteristics. By inserting an additional transmission line into a conventional NGD circuit, the proposed circuit provides further design parameters to obtain wideband group delay (GD) and to help reduce signal attenuation. As a result, the number of gain compensating amplifiers can be reduced, which can contribute to stable operation when integrated into RF systems. The multiple pole characteristics can provide wider NGD bandwidth and can be obtained by connecting resonators with slightly different center frequencies separated by quarter-wavelength transmission lines. For experimental validation, an NGD circuit with two poles GD characteristic is designed, simulated, and measured.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2089-2092
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• 2002

The PID controller have the simple structure and show the comparatively good control performance. Crystal Grower(FF-CZ150) melt polycrystalline silicon at the temperature of about 1450$^{\circ}C$, then grow it into a single crystalline ingot. The automatic diameter control system of the Crystal Grower has a good performance with only PD control. But it contain the integrator in the plant which has a long time delay. In this paper, we show the secondary approximate model and applies time delay controller which has good performance for the plant with long time delay. It will be able to improve the response characteristic against a standard input and a load disturbance.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.87-88
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• 2006

In this paper, we propose a new selective scanning scheme based on hand-off path information, which can provide an efficient reducing of delay time. This scheme eliminates almost of the scanning delay time by using Selective Scan based on Experience Path Table(SSEPT) algorithm and also completed hand-off within few milliseconds by using the next candidate channel indexing mechanism. Our scheme reduces the total number of scanning channels as well as the delay time on each channel. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of the scanning channels and the total delay time.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.434-439
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• 2019

This paper proposed a control algorithm to compensate the delay time to improve the signal to noise, and the proposed control algorithm estimate the target information to apply the continuous wave radar equation. The proposed control algorithm improves the output signal of each array element bv multiplying the weight of the receive signal to the signal to noise ratio. Radar radiate a signal in spatial and the target information is estimated by the echoed signal from the target. But the signal in the wireless communication environment occurs the delay time due to the multipath which appear human and natural structures. It is difficult to accurately estimate the desired information because of the degradation for the system performance due to the interference signal and the signal distortion. The target information can be improved by compensating the delay signal to apply the weight to the received signal by using the uniform linear array antenna. As a simulation result, we show that the performance of the proposed control algorithm and the non-compensated delay time are compared. The proposed control algorithm proved that the target distance estimation information is improved.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.243-248
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• 2010

This thesis proposes a power saving MAC protocol for LTE base station which utilizes different graded DRX/DTX(Discontinuous. Reception/Transmission) that specified by 3GPP(Third Generation Partnership Project). Considering QoS in UE, proposed MAC protocol controls adaptive DRX/DTX cycle. When Packet delay of UE is less than normal time, LTE base station economize power by increasing DRX/DTX. When Packet delay of UE is more than normal time, delay of UE is decreased by guaranteed QoS. It depends on the traffic which is sent by UE. The proposed method is more improve power saving performance than another method which is unchanged DRX/DTX by conditions. Especially when set DRX/DTX up in conditions, it will meet the requirements of UE. In this thesis, I propose an power saving MAC protocol in an environment where LTE base station are communicated with UE and prove improvement in performance through simulations.