• ETRI Journal
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• v.39 no.4
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• pp.582-591
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• 2017

To address the wire complexity problem in large-scale globally asynchronous, locally synchronous systems, a current-mode ternary encoding scheme was devised for a two-phase asynchronous protocol. However, for data transmission through a very long wire, few studies have been conducted on reducing the long propagation delay in current-mode circuits. Hence, this paper proposes a current steering logic (CSL) that is able to minimize the long delay for the devised current-mode ternary encoding scheme. The CSL creates pulse signals that charge or discharge the output signal in advance for a short period of time, and as a result, helps prevent a slack in the current signals. The encoder and decoder circuits employing the CSL are implemented using $0.25-{\mu}m$ CMOS technology. The results of an HSPICE simulation show that the normal and optimal mode operations of the CSL achieve a delay reduction of 11.8% and 28.1%, respectively, when compared to the original scheme for a 10-mm wire. They also reduce the power-delay product by 9.6% and 22.5%, respectively, at a data rate of 100 Mb/s for the same wire length.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.873-880
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• 2020

In this paper, we propose a guidance filter to estimate line of sight rate with strapdown seeker measurements and INS(Inertial Navigation System) information. The measurements of proposed guidance filter consisted of the LOS(Line of Sight) and relative position that can be calculated with the seeker's measurements, INS information and known target position, also the filter is based on an asynchronous filter to use outputs of the two sensors that are out of synchronous and period. Through the proposed filter, we can reduce the effect on parasitic loop that can be caused by using large time delay seeker and improve the estimation performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.23-29
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• 2004

In this paper, the asynchronous quasi dual-port SRAM employing a single port structure in SRAM embedded SOC (System On Chip) is proposed. External host can access the internal SRAM freely and the data on internal SRAM can be transferred to an another external circuitry without a synchronous signal of an external host, which operates as an asynchronous dual-port SRRAH The performances of the proposed circuits and control structure are verified through the simulation and we fabricated it using a 0.35um CMOS technology. As the results, the chip shows reduced area about 20% and saved power also 20% than conventional architectures.

• Journal of Communications and Networks
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• v.5 no.2
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• pp.150-156
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• 2003

In this paper, an uplink MC-CDMA system incorporating multiuser detection and smart antennas has been considered. The performance of asynchronous as well as synchronous system is studied over a correlated Rayleigh multipath slow fading channel. A simplified array-processing algorithm suitable for slow fading situation is investigated to overcome the heavy computational complexity associated with Eigen solutions. The effect of variable data rate in the system performance is considered and effectiveness of antenna array to handle high data rate is discussed. A brief investigation on the system performance degradation due to correlated channel is also carried out. Based on the extensive simulation carried out, the performance of the asynchronous uplink system is found dramatically improved with antenna array and multiuser detection. Asynchronicity and channel correlation are found to affect the system performance significantly. The investigated simpli- fied algorithm produces similar results as Eigen solutions in slow fading situation with much reduced complexity.

• Journal of Information Technology Applications and Management
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• v.9 no.1
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• pp.61-70
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• 2002

There are a lot of shopping malls in Internet and most of consumers want to buy good goods in cheap price through the shopping malls. To support them, many sites for price comparison are constructed. But man or woman search many shopping malls and insert their price informations into database that the price comparison sites own. To overcome this disadvantage, virtual shopping malls are builded. These virtual shopping malls are connected and cooperated a lot of affiliated existing shopping malls for the cheapest price information. But, these virtual shopping mall are connected to those existing shopping malls in synchronous. So If they are connected to many existing shopping malls, we have to wait long time because of searching for many existing shopping malls. In this paper, we designed and implemented a virtual shopping mall that connect to many existing shopping malls in asynchronous. For a asynchronous communication between this virtual shopping mall and many existing shopping malls, we used JMS (Java Message Service) that is a standard Java API for MOM (Message-Oriented Middleware).

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1968-1971
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• 2002

In this paper, we have presented a test- ing method for a kind of asynchronous circuits. Tar- get circuit model is the 3D machine that is one of the most successful implementation of extended burst-mode (XBM) machines. We present a high-level test generation method for the 3D machine using the specification of the circuit. We also present a gate-level test pattern generation method using a synchronous test pattern generator. Experimental results show that the combination of the above two methods achieves high fault coverage over 3D machines and saves test generation time.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1345-1350
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• 2003

Principal component analysis based two-dimensional (PCA-2D) correlation analysis is applied to FTIR spectra of polystyrene/methyl ethyl ketone/toluene solution mixture during the solvent evaporation. Substantial amount of artificial noise were added to the experimental data to demonstrate the practical noise-suppressing benefit of PCA-2D technique. 2D correlation analysis of the reconstructed data matrix from PCA loading vectors and scores successfully extracted only the most important features of synchronicity and asynchronicity without interference from noise or insignificant minor components. 2D correlation spectra constructed with only one principal component yield strictly synchronous response with no discernible a asynchronous features, while those involving at least two or more principal components generated meaningful asynchronous 2D correlation spectra. Deliberate manipulation of the rank of the reconstructed data matrix, by choosing the appropriate number and type of PCs, yields potentially more refined 2D correlation spectra.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1203-1211
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• 1999

Checkpointing is the one of fault-tolerant techniques to restore faults and to restart job fast. Checkpointing algorithms in distributed systems have been studied for many years. These algorithms can be classified into synchronous Checkpointing algorithms and asynchronous Checkpoiting algorithms. In this paper, we propose an independent Checkpointing algorithm that has a minimum Checkpointing counts equal to periodic Checkpointing algorithm, and relatively short rollback distance at faulty situation. Checkpointing count is directly related to task completion time in a fault-free situation and short rollback distance is directly related to task completion time in a faulty situation. The proposed algorithm is compared with the previously proposed asynchronous Checkpointing algorithms using simulation. In the simulation, the proposed Checkpointing algorithm produces better results than other algorithms in terms of task completion time in fault-free as well as faulty situations.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.272-275
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• 2022

The federated learning can be utilized in conjunction with the blockchain technology to provide good privacy protection and reward distribution mechanism in the field of intelligent IOT in edge computing scenarios. Nonetheless, the synchronous federated learning ignores the waiting delay due to the heterogeneity of edge devices (different computing power, communication bandwidth, and dataset size). Moreover, the potential of smart contracts was not fully explored to do some flexible design. This paper investigates the fusion application based on the FLchain, which is the combination of asynchronous federated learning and blockchain, discusses the communication optimization, and explores the feasible design of smart contract to solve some problems.

• Journal of Industrial Convergence
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• v.20 no.3
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• pp.11-21
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• 2022

The purpose of this study is to provide fundamental background to improve the quality of teaching and learning performance in online classes by analyzing the students' learning experience aspects on online environment. This study explores the relationship between learning experience and teaching and learning performance according to the online classes types(synchronous/asynchronous class), and identifies the mediation effect of students' perception and attitude toward online classes using Structural Equations Model(SEM). The findings are shown as follows: First, learning experience has positive effect on teaching and learning performance statistically. Second, learning experience has different effect on teaching and learning performance depending on the type of online classes. Specifically, learning experience in synchronous environment has higher influence on teaching and learning performance than in asynchronous environment. On the other hand, perception and attitude toward online classes have greater influence on teaching and learning performance in asynchronous class than in synchronous class. Lastly, the students' perception and attitude toward online classes do not have mediation effects significantly in the relationship between learning experience and teaching and learning performance. The result of this study can be a guide for researcher to approach to teaching and learning performance in online environment of university.