• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.6
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• pp.333-351
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• 2008

Transmission control protocols have to overcome common problems in wireless networks. TCP employing both packet loss discrimination mechanism and available bandwidth estimation algorithm, known as the good existing solution, shows significant performance enhancement in wireless networks. For instance, TCP New Jersey which exhibits high throughput in wireless networks intends to improve TCP performance by using available bandwidth estimation and congestion warning. Even though it achieves 17% and 85% improvements in terms of goodput over TCP Westwood and TCP Reno, respectively, we further improve it by exploring maximized available bandwidth estimation, handling bit-error-rate error recovery, and effective adjustment of sending rate for retransmission timeout. Hence, we propose TCP NJ+, showing that for up to 5% packet loss rate, it outperforms other TCP variants by 19% to 104% in terms of goodput when the network is in bi-directional background traffic.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.11
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• pp.87-93
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• 2020

A key component of aviation safety is to eliminate the errors in commercial aircraft air data systems to ensure stable aviation operation. Although the technical aspects such as the maintenance and inspection play a pertinent role, human errors are expected to have a similar or even larger influence on the aviation safety. Aviation maintenance and inspection tasks are often performed by a complex organization, in which individuals perform a variety of tasks in an environment involving time pressure, sparse feedback, and complex conditions. These situational characteristics, combined with the general tendency of human error, may lead to various types of errors, which may have critical consequences such as accidents and loss of life. For instance, if an amber message "IAS DISAGREE" is displayed on the primary flight display while the aircraft is rolling on the runway to takeoff, the crew immediately performs a rejected takeoff operation and troubleshoots the air data system. This paper proposes alternative approaches to address the occurrence of defects due to the human factors involved in the practical processes of the air data system of commercial aircraft.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.475-484
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• 2021

The Android OS has quickly established itself with the smartphone market and is being applied in a variety of ways such as navigation and refrigerator panels. Existing terminals can implement services that require high precision while using RTOS that requires accurate execution time, but Android OS has a disadvantage in that it cannot provide high-precision real-time performance. In this paper, we propose a real-time communication method that operates in the Android OS. Real-time communication reduces the load using the UDP protocol, and configures the real-time operating system time tick through a high-precision timer in the kernel area. An Android application level library was created to implement real-time communication and compared with the existing Android library for real-time performance verification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.209-212
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• 2008

During several years, lots of industrial and individual products have been developed based on the text or graphic LCD module which has been gave the short developing period to the developer. With the advent of home networks and intelligent robots, the need for interaction between human and instruments has been increased. Recently, goods with a TFT-LCD come out. But in spite of a simple required performance, the complicated microprocessor, such as ARM processor, is required to interface the TFT-LCD and touch screen. Our research and development is to develope an embedded TFT-LCD module in order to use or apply to the goods through the simple interface by the general users as well as the developers. We adopt the RTOS(real time operating system) in order to operate TFT-LCD independently and various communication protocols are provided in order to offer the simple interface to users and developers.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.108-115
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• 2017

Generally, there are three ways to remove VOCs from the small painting booth; adsorption, burn and oxidation catalyst. RTO and RCO are high efficiency methods for removing VOCs. But they require large installation areas, which are not suitable for the small painting booth. And we need a new removing method because it is difficult to predict the A/C changing time and the recycle time. To solve these problems, we have developed the Arc plasma system which is simple and enable consecutive-use. It removes VOCs effectively and eco-friendly. In this study we have investigated the enrichment material and VOCs removal efficiency.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.177-195
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• 2005

The purpose of this study was to analyze the kinematic variables of ankle joints and EMG signal of the lower limbs muscle activity for the different walking speed. The subjects were 6 males of twenties. It was classified into three different walking speed-0.75m/s, 1.25m/s, 1.75m/s. The walking performances were filmed by high speed video camera and EMG signal was gained by ME3000P8 Measurement Unit. Tibialis anterior(TA), Gastrocnemius medial head(GM), Gastrocnemius lateral head(GL), Ssoleus(SO) were selected for the dorsiflexion and plantarflexion of the ankle joint. The result of this study were as follows: 1. In the gait cycle, The time parameters for the phases were showed significant difference without the terminal stance phase and terminal swing phase for the different walking speed. 2. The angle of ankle joint was no significant difference for each time point and MDF, MPF but increasing walking speed the angle had the increasing pattern slightly. 3. The angular velocity of ankle joint was showed the significant difference for LHC, RTO, RKC, LHU, MPF and MDF point along the walking speed. 4. TA was showed about 2-3 times muscle activity at the 1.75m/s than 1.25m/s in some phases. And it was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 0.75m/s. GM was showed about 2-3 times muscle activity in the 1.75m/s than 1.25m/s, and even much muscle activity at the 0.75m/s than 1.25m/s in some phases. GL was showed increasing pattern of muscle activity specially in the initial swing phase as the walking speed increased. SO was showed about 3 times muscle activity in the 1.75m/s than 1.25m/s during the plantarflexion of ankle joint. It was showed the similar muscle activity between the 0.75m/s and 1.25m/s but, showed a little much muscle activity in the 1.25m/s.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1603-1609
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• 2010

This Paper deals with a design, making a prtotype and test methods of Real-time towed Line Array Sensor Data processing board for fast data communication and long range data transmission with SFM(Serial FPDP Module) through Optic-fiber channel. Towed line array sensors are installed in Frigate and the each LAS A, B, C group data from LAS is packed a previously agreed protocol and transmitted to the signal processing unit. Considering the limited space of VME 6U size, LAS Data processing board is designed with MPC8265 PowerPC Controller of Freescale for main system control and Altera's CycloneIII FPGA for sensor data packing, self-test simulation data generation, S/W FIFO et cetera. LAS Data processing board have VxWorks, the RTOS(Real Time Operating System) that present many device drivers, peripheral control libraries on board for real-time data processing.

• The KIPS Transactions:PartC
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• v.11C no.2
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• pp.229-234
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• 2004

In this study, the performance is compared between RFC compatible normal TCP and several speed constraints Ignored TCP. To do these, the main algorithms that constraints the transmit rate of TCP are modified. We have modified TCP protocol stack in a Linux kernel to compare the speeds between the standard TCP and our modified TCP. We find that if the destination is short distance away from the source and packet error is scarce then the speed differences between normal and modified TCP nay be negligible. However, if the destination is far away from the source and slow start algorithm is not adopted then the transfer time for small file is different greatly In addition, if packet error occurred frequently, our modified TCP is faster than the standard TCP regardless of distance.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.3
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• pp.257-267
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• 2005

The real-time operating system(RTOS) simulator, one of the tools provided by RTOS development environment, allows users to develop and debug application programs even before the target hardware is ready. Thus, most of commercial RTOS development environments provide with RTOS simulator for the purpose. But they are implemented to simulate only functional aspects on a host system, so that it is not possible to estimate execution time of application programs on the target hardware. Since the real-time system has to complete program executions in predetermined time, the RTOS simulator that can estimate the execution time is yeW useful in the development phase. In this study, we develop a machine instruction-level RTOS simulator that is able to estimate execution time of application programs on a target hardware, and prove its functionality and accuracy by using test .programs.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.1
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• pp.33-40
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• 2017

In this Paper, Analyse the Steady State Behavior of TCP and TFRC with Packet Error when both TCP and TFRC Flows Co-exist in the Network. First, Model the Network with TCP and TFRC Connections as a Discrete Time System. Second, Calculate Average Round Trip Time of the Packet Between Source and Destination on Packet Loss Environment. Then Derive the Steady State Performance i.e. Throughput of TCP and TFRC, and Average Buffer Size of RED Router Based on the Analytic Network Model. The Throughput of TCP and TFRC Connection Decrease Rapidly with the Growth of Sending Window Size and Their Transmission Rate but Their Declines become Smoothly when the Number of Sending Window Arrives on Threshold Value. The Average Queue Length of RED Router Increases Slowly on Low Transmission Rate but Increases Rapidly on High Transmission Rate.