• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2043-2054
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• 1996

In this paper, Digital Delay Locked Loop(DDLL) is designed, implemented and analysed by experiment whose results show that it is possible to track the received signal by this scheme. Designed digital DLL has an advantage that it is not needed to maintain gain balance between early and late channels, which has been problem with an analog DLL. Also DDLL has more improved noise performance compared to analog DLL due to noise level limitation and noise cancellation characteristics. For various loop parameters, their effects on loop performance are analysed and simulated. Proposed DDLL is the first attempt as a digital approach in code tracking loop and it is expected to be a good reference for spread spectrum communication research.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.387-393
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• 2009

In this paper, we have considered the network performance of the VoIP service with the measurement by an emulator, and analyzed the major factors to affect its performance. Also, we have used the measured values to investigate the traffic variations, where their values were observed in the commercial operated network after the delay, jitter and packet loss, and loss compensation methods were applied as the dominant elements. It is expected that our presented results will be a good data to provide the high-quality of voice service in the Internet.

• East Asian Economic Review
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• v.24 no.4
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• pp.417-440
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• 2020

The coronavirus pandemic of 2019-20 confronted fiscally dominant regimes around the world with the question of whether the large deficits caused by the health crisis should be monetized or financed by issuing debt. The unpleasant monetarist arithmetic of Sargent and Wallace (1981) states that in a fiscally dominant regime tighter money now can cause higher inflation in the future. In spite of the qualifier 'unpleasant,' this result is positive in nature, and, therefore, void of normative content. I analyze conditions under which it is optimal in a welfare sense for the central bank to delay inflation by issuing debt to finance part of the fiscal deficit. The analysis is conducted in the context of a model in which the aforementioned monetarist arithmetic holds, in the sense that if the government finds it optimal to delay inflation, it does so knowing that it would result in higher inflation in the future. The central result of the paper is that delaying inflation is optimal when the fiscal deficit is expected to decline over time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.86-96
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• 2006

In recent year, EPON(Ethernet PON) system is expected to be more attractive solutions for high speed, broadband access networks in next generation access networks due to the conversionce of low-cost ethernet equipment and low-cost fiber infrastructure. Upstream channel control algorithm is essential to hare upstream bandwidth in EPON. In this paper, we suggest HUHG(High Utilization and Hybrid Granting) algorithm for supporting high bandwidth utilization and QoS for different service class. This algorithm improves bandwidth utilization as removing or diminishing idle time of upstream channel using characteristics of fixed EF(Expedited Forwarding) sub-cycle. The proposed algorithm also minimizes the packet delay and delay variation of EF class. We conduct detailed simulation experiments using OPNET to study the performance and validate the effectiveness of the proposed algorithm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.163-170
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• 2016

Heading time is important element for yield and quality in crops. Among day length and temperature which influence on heading, temperature effect has not been investigated well. To investigate temperature effect on heading, heading date and plant growth characters were checked under the low and high temperature conditions in short day length. Analyzing heading date of six Korean varieties under the high and low temperature condition, heading date of varieties were delayed under low temperature. In the low temperature condition, dry weight and area of leaf were reduced. Varieties showing more delay of heading under low temperature also showed more reduction in leaf area. After selecting three varieties showing significant difference in leaf growth and heading date under different temperature conditions, nutrient contents of plant were analyzed. Nitrogen content was reduced in leaf and shoot under the low temperature condition. OsNRT2.3, nitrate transporter, was significantly down regulated in varieties showing more heading delay. Available phosphate content was decreased in leaf, but increased in shoot due to reduction of phosphate mobility. OsPT1, phosphate transporter regulating phosphate uptake, was more down regulated in varieties showing more heading delay. OsPT6, phosphate transporter regulating phosphate transport in plant, was also significantly down regulated in those varieties. With these data, we expected that active nitrogen and available phosphate uptake and transport in plant would increase leaf growth then might reduce heading delay under the low temperature condition.

• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.385-395
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• 2017

This study deals with the small-scale roundabout. The purpose of this study is to analyze the average delay of vehicle in roundabout, and suggest the efficient planning and design standard. In pursuing the above, this study gives particular attentions to analyzing the average delay time according to the inscribed circle diameter, speed of circulatory roadway lane and traffic volume. The operational efficiencies of 96 scenarios (3 sizes of inscribed circle diameter ${\times}$ 4 types of circulatory roadway speed ${\times}$ traffic volume) are analyzed using VISSIM (Verkehr In $St{\ddot{a}}dten$-SIMulationsmodell). The main results are as follows. First, the optimal design speed of small-scale roundabout are derived from the above scenario analysis. Second, the traffic volume of LOS D is estimated to be 2,180-2,740pcph. Third, the traffic volume of LOS F that is required to improve is above 2.780pcph. The results might be expected to give some implications to providing the countermeasures for the operational efficiency of roundabout.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.859-862
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• 1999

We designed a 128-tap FIR filter for a modem which complies with ITU-T V.32. We adopted pipeline technique and realized delay-taps with two ring-buffers. The multiplier in this filter carries out 2's complement fixed-point multiplication of 14bit $\times$ 16bit. The designed filter is expected to operate at 50MHz.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.2
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• pp.175-182
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• 1993

The probabilistic order level inventory model is developed when a supplier allows some credit period T for settling the accounts for purchase quantity. The credit period T is known constant. Mathematical models are derived for both the cases i) T'.leq. T and ii) T'>T. Expressions are derived for average expected total cost of the system, the optimum cycle time and for obtaining optimum order level S = S$_{0}$ in each case. The exmaples are given to illustrate the model.

• Korean Journal of Construction Engineering and Management
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• v.24 no.1
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• pp.12-20
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• 2023

To calculate the amount of owner-caused and contractor-caused delays based on a simplified delay analysis, which has been customarily used in Korea, has a limitation in reflecting the impact of the concurrent delay and the acceleration work. It also resulted in the apportionment of liquidated damages by applying the ratio of the number of delays between the owner and the contractor. This study analyzes that the conventional method does not meet the international standards. In order to improve the problem of construction delay analysis and the apportionment of liquidated damages based on it, owner delays, contractor delays, concurrent delays, and the impact of acceleration should be analyzed together. This study suggests that in the apportionment of liquidated damages, the extension of time should be extended by the sum of concurrent delays and the owner-caused delays, and liquidated damages should be imposed on delays incurred after the extension of time. It can be seen that it conforms to the international standards. The results of this study are expected to contribute to improving the problems of delay analysis and liquidated damages calculation, which have been conventionally accepted.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2531-2533
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• 2002

In this paper, we evaluate feasibility of an object-oriented method in a distributed real-time control environment through the prediction of delay expected. We adopt CAN as the distributed network and the application layer of the CAN is composed of client/server communication model of COM and surroundings for the support of real-time capability of the COM. Mathematical models formalizing delays which are predicted to invoke in the COM architecture are proposed. Sensors and actuators which are widely used in distributed network-based systems are represented by COM objects in this paper. It is expected that the mathematical models can be used to protect distributed network-based systems from violation of real-time features by the COM.