• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2463-2482
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• 2016

Cloud services are often provisioned to their customers using user-friendly web browsers with flexible and rich plug-in environments. Delay is one of the fundamental performance metrics of these web-based services. Commonly-used network measurement tools usually only measure network delay and it may be difficult to infer the web-delay performance using only network layer measurement approaches. In this paper, we propose to evaluate the application layer delay in a browser-based network measurement platform using engineered scripts. We conducted a delay measurement study using instrumented scripts in the proposed browser-based measurement platform. Our investigation included a comparison study of three browser-scripting delay measurement methods, including Java applet, JSP and Flash ActionScript. We developed a browser-based delay measurement testbed over the Internet so that different delay measurement tools could be evaluated in the same real network environment including typical Internet paths and the Baidu cloud. We also decomposed the components of the end-to-end delay process of the above measurements to reveal the difference and relationship between the network-layer delay and the application-layer delay. Our measurement results characterize the stochastic properties of the application-layer delay over real Internet paths, and how these properties vary from the underlying network layer delay. This browser-scripting measurement approach can be easily deployed on different cloud service platforms to inspect their application-layer delay performance between end clients and the cloud platforms. Our measurement results may provide insights into designing new cloud services with enhanced quality-of-experience perceived by cloud users.

• 지식정보인프라
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• 통권7호
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• pp.134-140
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• 2001

To know about the performance of KREONET, we installed an active network performance measurement tool, PingER. For customization, we modified its architecture and some codes. Although this customization is a minor change of PingER, it gives much benefit and convenience for both operators and users. Using PingER, we can measure the effect of the STAR TAP link. The new networking through the link is a little bit slower than the previous networking. But the new link shows far fewer packet losses and provides more reliable networking.

• 동력기계공학회지
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• 제11권1호
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• pp.28-32
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• 2007

This research proposed that development of wireless condition monitoring system using WLAN network. It offers the prospect of improved performance that removed a current a coaxial cable and reduced overall cost of condition monitoring. Recently, there is an interesting concern for wireless system as an infrastructure technology construct ubiquitous computing environment in the future. High performance computing board makes minimization with integrate of a various functions which support wireless LAN network. Instead of wired coaxial cable using measurement system in industry, wireless LAN network assists industry automation and engineer's convenience. Developed system adapted wireless LAN network on shipboard with engine room and deck house, it also executes wireless measurement test on 8500TEU containership.

• 융합보안논문지
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• 제12권6호
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• pp.11-17
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• 2012

네트워크보안 성능평가는 복잡하고 다양한 시스템 환경에서 특정한 단일성능 측정 만으로는 성능평가 측정자체의 의미와 평가결과의 신뢰성이 한계일 수 밖에 없다. 본 논문에서는 보안 QoS의 MOS 측정기법을 사용한 보안기능 만족도 측정방법을 제시한다. 그 내용은 네트워크보안 QoS 만족도에 대한 MOS(Mean Opinion Score) 평가사양 및 운용방법을 개발하여 향후 정보시스템에 대한 고객의 만족도 평가에 활용될 수 있는 QoS 측정/분석 모델을 운용현장에서 활용토록한다. 시스템공급자(개발업체)와 시스템소비자(사용자) 모두가 성능측정 결과를 이용할 수 있도록 가능한 수준의 객관화된 형태의 기준과 방법체계를 개발한다. 개발내용은 보안기능, 네트워킹 기능과 이 두 기능을 종합적으로 평가하는 3개영역의 성능이 상호 연계되는 성능측정 방법론이다. 본연구의 제안 방법론을 사용하여 체계적인 측정환경을 설계 할 경우 운용시스템상에서 보안 QoS의 만족도 산출이 가능하다. 앞으로 다양한 성능측정 기준과 성능측정 방법을 추가적으로 확장하여 네트워크 보안시스템 만족도 평가방법을 업그레이드 시켜나가야 할 것 이다.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2533-2540
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• 2009

네트워크나 네트워크를 구성하는 시스템에서 프로토콜을 처리하는 성능은 중요한 목표가 되며, 이를 측정하는 과정은 네트워크 구성이나 시스템 개발에 있어서 필수적인 요소이다. 프로젝션(Projection)은 주어진 벡터(Vector)를 각 좌표 평면에서 대응되는 점으로 변환시키는 것으로, 프로젝션 기법은 또한 벡터수학을 응용하여 공학에서 많이 사용되는 방법으로서 여러 성분들로 구성된 것에서 측정목표에 관련된 원하는 특정 성분들만을 고려하는 방법론이다. 본 논문에서는 차세대 네트워크에서 인터넷 텔레포니를 위한 대표적인 표준 호 처리프로토콜인 SIP의 성능 측정방법으로, 불필요한 경로들과 그에 해당하는 처리루틴들을 제거한 프로젝션된 프로토콜만으로 성능을 측정함으로써 성능 측정 시 구현 및 자원의 사용면에서 효과적인 방법을 제안한다. 또한 제안된 방법을 이용하여 SIP 프록시 서버의 성능을 측정하는 과정을 제시한다.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1324-1327
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• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network

• 한국IT서비스학회지
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• 제11권1호
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• pp.239-246
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• 2012

The user increases around the WiBro and in which the mobile broad band service is the wireless internet base technology HSDPA, that is the cellular phone foundation technique, and moreover the issue about the user effective quality guarantee emerges but the quality control of the wireless network is the incomplete actual condition. Therefore, the reliability verification according to the development of the system for the performance measure for the continued wireless data service and it and evaluation are needed for the quality control. In this paper, the wireless data service quality measurement system was implemented with the design. The same test environment as the existing network performance measurement program was built for the reliability verification of the embodied device for measuring quality and evaluation and the cost performance was performed. It could confirm that design and embodied wireless data service quality measurement system operated accurately in this paper through the quality measure result value analysis.

• 한국구조물진단유지관리공학회 논문집
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• 제3권2호
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• pp.221-232
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• 1999

This study investigates the applicability and design scheme of fieldbus network in the measurement system used for precise and safe construction as well as efficient maintenance of bridges. In order to maximize the function and performance of bridge monitoring system, this study introduces the CAN(Controller Area Network), one of the fieldbus protocols, in the measurement system of bridges. This study presents the implementation method of CAN on the monitoring system of bridge, and also proposes a bandwidth allocation scheme for the design of network. The validity of the proposed CAN design method is verified through a simulation experiment. It is shown that the CAN can be readily applicable to the measurement system of bridges.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5948-5971
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• 2019

Estimating loss rates with the packet traces captured from some point in the middle of the network has received much attention within the research community. Meanwhile, existing intermediate-point methods like [1] require the capturing system to capture all the TCP traffic that crosses the border of an access network (typically Gigabit network) destined to or coming from the Internet. However, limited to the performance of current hardware and software, capturing network traffic in a Gigabit environment is still a challenging task. The uncaptured packets will affect the total number of captured packets and the estimated number of packet losses, which eventually affects the accuracy of the estimated loss rate. Therefore, to obtain more accurate loss rate, a method of strengthening packet loss measurement from the network intermediate point is proposed in this paper. Through constructing a series of heuristic rules and leveraging the binomial distribution principle, the proposed method realizes the compensation for the estimated loss rate. Also, experiment results show that although there is no increase in the proportion of accurate estimates, the compensation makes the majority of estimates closer to the accurate ones.