• ETRI Journal
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• v.45 no.6
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• pp.974-981
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• 2023

This paper presents a transition-limited pulse-amplitude modulation (TLPAM) signaling method to enable a high data rate and robust wireline communications. TLPAM signaling addresses the impact of high intersymbol interference (ISI) ratios in conventional M-ary PAM signaling methods by limiting the maximum voltage transition level between adjacent symbols. The implementation of a TLPAM signaling encoder is realized by setting back the most significant bits (MSBs) in the queue. The correlation between TLPAM's maximum transition level, effective data rate, and eye width/height is analyzed with various channel loss parameters, followed by characterization and measurement results with a realistic channel setup. The analysis and experimental results reveal the effectiveness of the proposed TLPAM signaling scheme for achieving a high data rate with minimal interference.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.82-88
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• 2001

The demands of high data transfer rate and high recording density in optical disk memory device are being increased. In this paper, 4 design parameters for next generation optical disk are investigated. As for the high data transfer rate, two design parameters such as driving acceleration and transmissibility are introduced. As the high recording density is concerned, the minimum linearity and the tilt of the actuator are introduced. Two kinds of pickup actuator are used to evaluate the validity of the parameters through the simulation and the experiment. The 4-wire actuator has good linearity but bad stability and tilt characteristics, while the rotary and axis actuator has good stability for the external vibration but bad linearity. It is demonstrated that the newly proposed design parameters are available to design and evaluate quantitatively the performance of the actuator for the next generation optical disk.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.293-298
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• 2017

Recently, much research has been devoted to implementing and provisioning high-performance computing environment using clusters with multiple computers and high-performance networking technologies. In-memory based Key-Value stores, such as Redis or Memcached, are widely used in high performance cluster environments to improve the data processing performance. We can distribute data at different storage nodes, and each computing node can access it at a high speed using these In-memory based Key-Value stores. InfiniBand is a de-facto technology that is widely used to interconnect each node of a cluster. In this paper, we propose a new data pre-fetching scheme for Key-Value store based on high performance clusters to improve the performance. The proposed scheme utilizes the data transfer characteristics of InfiniBand. The results of the simulation show that the proposed scheme can reduce the data transfer time by up to about 28%.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.78-87
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• 2016

This study experimentally investigated the effects of droplet temperature on the heat transfer characteristics during collision of a single droplet on a heated wall above the Leidenfrost temperature. Experiments were performed by varying temperature from 40 to $100^{\circ}C$ while the collision velocity and wall temperature were maintained constant at 0.7 m/s at $500^{\circ}C$, respectively. Evolution of temperature distribution at the droplet-wall interface as well as collision dynamics of the droplet were simultaneously recorded using synchronized high-speed video and infrared cameras. The local heat flux distribution at the collision surface was deduced using the measured temperature distribution data. Various physical parameters, including residence time, local heat flux distribution, heat transfer rate, heat transfer effectiveness and vapor film thickness, were measured from the visualization data. The results showed that increase in droplet temperature reduces the residence time and increases the vapor film thickness. This ultimately results in reduction in the total heat transfer by conduction through the vapor film during droplet-wall collision.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.333-335
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• 2006

In this page, we developed the inspection system for automobile parts using the laser vision sensor. Laser vision sensor has gotten 2 dimensions information and third dimension information of laser vision camera using the vision camera. Used JIG and ROBOT for inspection position transfer. Also, computer integration system developed that control system component pal1s and manage data measurement information. Compare sensor measurement result with CAD Data and verified measurement result effectiveness taking advantage of CAD to get information of measurement object.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2868-2870
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• 2000

Vision systems need to have high speed transfer methods for transferring large data. After PC accepts PCL, PCI becomes a more effective method for data translation. PCI substitutes previous ISA. This paper proposes an architecture of vision system and window driver based on PCI.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.817-824
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• 2015

Experiments were carried out to investigate the flow and mass transfer characteristics of an orifice nozzle. Measurements of primary and suction flow rates, dissolved oxygen concentration, and electric power were obtained. Vertically injected mixed-jet images were captured by a direct visualization technique with a high speed camera unit. The mass ratio, volumetric mass transfer coefficient, and mass transfer performance were calculated using the measured data. As the primary flow pressure increases, the mass ratio decreases slightly, while the volumetric mass transfer coefficient and electric power increase. As the primary flow pressure increases and the mass ratio decreases, the mass transfer rate increases because of the fine bubbles and wider distribution of the bubbles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.367-374
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• 2007

In this paper, we investigate the features of scientific remote collaborative applications. The presented features are the high speed disk access, the high speed transportation protocol, and the dedicated light path, which are for the high performance of remote end-to-end collaboration. In the environment that satisfies the features, we achieve 4.7Gbps peak throughput between Korea and U.S.A.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.775-779
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• 2001

In optical disk drive (ODD), disk rotation speed has been increasing rapidly to achieve high data transfer rate. High servo bandwidths for focusing and tracking actuator are required to follow dynamic disturbance by high rotation speed in ODD. However, the servo bandwidth is significantly limited by some vibration modes which are induced by the flexibility of moving part. In this work, the vibration modes affecting bandwidth of actuators are suppressed by modifying actuating force by VCM. For this, the relation between the horizontal component of the actuating force and vibration mode is analyzed and force characteristic affecting to vibration mode is obtained through electromagnetic and structural analysis using simulation program.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1097-1108
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• 2019

In VLBI(Very Long Baseline Interferometry), the observed data created in many observatories which are far away from each other should be collected in correlation center for data analysis. Traditionally, observed data is moved by transportation such as car or airplane. But it is replaced with data transfer over the network rapidly as the advancement of information technology, and therefore, international cooperative research is also now more widely expanding. e-KVN(electronic Korean VLBI Network) has been upgraded two times so the network interface of KVN has been evolved to the highest specification of 100GbE. During this time period, the portion of network usage for VLBI observations and experiments in KVN has been increased exponentially. In this paper, we describe KVN VLBI system and network technology for the performance upgrade and advanced status monitoring between three radio astronomy observatories and Daejeon correlation center with KREONET(Korea Research Environment Open NETwork). Furthermore, future plan of e-KVN for the implementation of wide band VLBI observation will be also briefly discussed.