• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.437-442
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• 2005

The measurement of RTT (Round Trip Time) can be used for the analysis of Internet congestion. However, simple measuring of RTT which measures only hun around time of a packet can not infer a packet forward/backward delay variation. In this thesis, we present a new algorithm which can be used for the estimation of forward/backward delay variation of packets. These delay variations are implication of network congestion state. In this algorithm, the reference forward/backward delay can be determined based on the minimum RTT value. The delay variation of each packet can be calculated by comparing reference delay with the packet delay. We verified our proposed algorithm by NS-2 simulation and delay measuring in a real network.

• Fire Science and Engineering
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• v.24 no.1
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• pp.8-14
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• 2010

It is more important to study for reducing the evacuation time of occupant in fire, because the building has been taller and deeper. It has known that elevator was not safe in fire situation. So, the using elevator for evacuation has been prohibited. But the study of elevator evacuation is progressed with designing the elevator safe from flame and smoke. This study analyze the consideration factors for the calculation of elevator evacuation time. The factors for elevator evacuation calculation is starting time, round trip time. And round trip time is divided into standing time and travel time. The elevator evacuation time can be calculated by compounding these factors and adding the efficiency. For using elevator to evacuate, we need additional study for smoke control, compartment, water proof and safe electric power supply.

• Smart Media Journal
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• v.8 no.3
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• pp.53-61
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• 2019

In this paper, designing and implementing multi-communication middleware in multi-thread environmet through event-based synchronization method are proposed for stable data transmission of electronic optical equipment, which requires combining camera and various sensors to process multiple high-speed data. To verify the performance of the implemented communication middleware, image data and sensor data were sent to compare differences in reception-based and transmission-based cycles, and the maximum number of communication possibilities to transmit and process multiple was measured and analyzed. In addition, the proposed communication middleware's performance was verified through experiments such as validating the integrity of the transmitted data and measuring the Round Trip Time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.259-266
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• 2012

Malicious rogue AP has been used for variety attacks such as packet sniffing and Man-In-The-Middle Attack. It is used for the purpose of data leakage via 3G network within companies, and the unauthorized AP could be a reason of security incidents even though it is not intended. In this paper, we propose the method for detecting unauthorized access point over 3G networks throughout the RTT (Round Trip Time) value for classification. Through the experiments, we show that the method can classify the AP which is installed by normal way and the AP over 3G networks successfully.

• Journal of IKEEE
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• v.27 no.4
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• pp.617-623
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• 2023

With the evolution of communication networks, there is a growing demand for stable high-speed data connections to support services relying on large-capacity data. The increasing volume of packet data aggregated from user devices underscores the significance of quality diagnostics for the backhaul network, an intermediate link transmitting data to the core network. This paper conducts empirical research on techniques to diagnose issues within the backhaul network through practical case studies, through diagnosing various factors such as circuit bandwidth, speed disparities within switches, network segment-specific buffer sizes, routing policies, among other factors that could potentially cause RTT (Round Trip Time) delays and performance degradation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.61-69
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• 2019

The concept of carsharing involves sharing a small number of reserved cars to be used individually by a larger number of people as required. This study examines the operating parameters of one-way carsharing systems in order to determine the appropriate operating conditions that minimizes the lost sales rate. Five operating parameters are tested in this study: the number of stations, the average number of vehicles per station, the rate of one-way trip, the average number of staffs per station, and the relocation policy. The performance of round-trip carsharing systems is also compared to that of one-way carsharing systems. A simulation model is developed and simulations are performed to determine the appropriate combination of operating parameter and levels. The simulation results show that the average number of vehicles per station is the most critical parameter. Other key findings obtained from this research are as follows. First, applying the appropriate relocation policy to one-way carsharing systems can allow more customers to rent vehicles than the traditional round-trip carsharing systems. Second, the appropriate relocation policy should be selected based on the average number of vehicles per station in order to minimize the lost sales rate. Third, the number of stations does not affect the lost sales rate. This study findings will provide tools to understand impact of the carsharing system parameters on the efficiency of the carsharing operations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.26-37
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• 2019

Recently, standardization of installation progress and technology of site acceptance test(SAT) for energy storage system(ESS) are being required due to performance of ESS depending on working condition and environment even though the quality and safety of each component of ESS　is guaranteed. And also, it has been required to perform not only performance testing by H/W equipments but also performance verification by S/W tool, in order to more accurately and reliably validate the performance of the ESS in advanced countries. Therefore, this paper proposes evaluation algorithm for SAT to evaluate performance of ESS and presents modeling of SAT test equipment for ESS by using PSCAD/EMTDC. Furthermore, 30[kW] scaled portable test equipments is implemented based on the proposed algorithm and modeling. From the various simulation and test results, it is confirmed that performance of ESS related to characteristics of capacity and Round-trip efficiency, Duty-cycle efficiency, low voltage ride through(LVRT) and Anti-islanding can be accurately evaluated and that the simulation results of PSCAD/EMTDC are identical to test results of 30[kW] test equipment.

• Proceedings of the Acoustical Society of Korea Conference
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• 1985.10a
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• pp.23-26
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• 1985

압전형 초음파 변화자의 특성을 압전체, matching layer, backing, 매질, tuning 및 구동 회로를 고려하여 해석하였다. 압전체는 KLM 모델을 이용하였고 모델변수를 실험적으로 추정하여 시뮬레이션에 대입하였다. 실험적인 RTIL(Round Trip Insertion Loss)은 면반사(plane reflection)에 대한 pulse-echo를 측정하여 계산되었으며, 이론치와 비교할 때 6-dB 주파수 대역내에서 2-dB 이하의 오차가 관찰되었다.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.617-622
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• 2000

In this paper proposed is an $H_{\ifty}$ based flow controller for the ATM networks. The round trip time-delay uncertainty is taken into account and robustness of the proposed controller is analyzed. Maximum allowable time-delay uncertainties are computed with different weightings on performance and robustness. And discussed is a time-domain implementation method of the proposed controller. Time domain simulation with realistic environment demonstrates that the performance of the proposed controller is much better than that of conventional one.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.350-351
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• 2011

In this paper we study the impact of heterogeneous round trip times on multipath TCP (MPTCP) performance via analysis the fluid model and simulation. Using parameter 'a' in MPTCP can alleviate poor performance due to divergent RTTs between paths. Moreover, divergent RTIs in MPTCP can affect response to changes in the network conditions.