• 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.

• Current Optics and Photonics
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• 제8권2호
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• pp.170-182
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• 2024

The dimensional accuracy and consistency of a dual oil circuit centrifugal fuel nozzle are important for fuel distribution and combustion efficiency in an engine combustion chamber. A point cloud measurement method was proposed to solve the geometric accuracy detection problem for the fuel nozzle. An improved variance focus measure operator was used to extract the depth point cloud. Compared with other traditional sharpness evaluation functions, the improved operator can generate the best evaluation curve, and has the least noise and the shortest calculation time. The experimental results of point cloud slicing measurement show that the best window size is 24 × 24 pixels. In the height measurement experiment of the standard sample block, the relative error is 2.32%, and in the fuel nozzle cone angle measurement experiment, the relative error is 2.46%, which can meet the high precision requirements of a dual oil circuit centrifugal fuel nozzle.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.39-44
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• 2021

Since the recent Corona 19, the importance of cloud computing is increasing, and at the same time, competition among clouds is intensifying. Cloud companies are competing for survival by promoting various management innovation methods for continuous growth and development amid a rapidly changing business environment. They are also increasingly interested in performance management in their operations and growth. In this paper, we propose Cloud BSC, an IT BSC-based performance measurement model for cloud enterprise performance management. The validity of the proposed model is verified through statistical analysis and causal analysis. Eventually, the proposed model is expected to be utilized as a management evaluation tool that can provide useful performance analysis information to cloud companies.

• 한국분무공학회지
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• 제20권4호
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• pp.230-235
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• 2015

The demands for reliable particle cloud temperature measurement exist in many process industries and scientific researches. Particle cloud temperature measurements depend on radiation thermometry at two or more color bands. In this study, we developed a sensitive, fast response and compact online infrared two-color probe to measure the temperature of a particle cloud in a phase of two field flow (solid-gas). The probe employs a detector contained two InGaAs photodiodes with different spectral responses in the same optical path, which allowed a compact probe design. The probe was designed to suit temperature measurements in harsh environments with the advantage of durability. The developed two-color probe is capable of detecting particle cloud temperature as low as $300^{\circ}C$, under dynamic conditions.

• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.605-610
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• 2014

Clouds play an important role in climate change, in the prediction of local weather, and also in aviation safety when instrument assisted flying is unavailable. Presently, various ground-based instruments used for the measurements of the cloud base height or velocity. Lidar techniques are powerful and have many applications in climate studies, including the clouds' temperature measurement, the aerosol particle properties, etc. Otherwise, it is very circumscribed in cloud velocity measurements because there is no Doppler effect if the clouds move in the perpendicular direction to the laser beam path of Doppler lidar. In this paper, we present a method for the measurement of cloud velocity using lidar's range detection and DIC (Digital Image Correlation) system to overcome the disadvantage of Doppler lidar. The lidar system acquires the distance to the cloud, and the cloud images are tracked using the developed fast correlation algorithm of DIC. We acquired the velocities of clouds using the calculated distance and DIC algorithm. The measurement values had a linear distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.305-325
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• 2014

In cloud computing infrastructure, current virtual machine trust measurement methods have many shortcomings in dynamism, security and concurrency. In this paper, we present a new method to measure the trust of virtual machine. Firstly, we propose "behavior trace" to describe the state of virtual machine. Behavior trace is a sequence of behaviors. The measurement of behavior trace is conducted on the basis of anticipated trusted behavior, which not only ensures security of the virtual machine during runtime stage but also reduces complexity of the trust measurement. Based on the behavior trace, we present a Dynamic Tree Style Trust Measurement Model (DTSTM). In this model, the measurement of system domain and user domain is separated, which enhances the extensibility, security and concurrency of the measurement. Finally, based on System Call Interceptor (SCI) and Virtual Machine Introspection (VMI) technology, we implement a DTSTM prototype system for virtual machine trust measurement. Experimental results demonstrate that the system can effectively verify the trust of virtual machine and requires a relatively low performance overhead.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.262-268
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• 2005

In this work, to obtain the detailed information about lightning electromagnetic field waveforms, the LabVIEW based-measurement system of time-changing magnetic fields was designed and constructed. The frequency bandwidth of the magnetic field measuring system ranges from 300 [Hz] to 1 [MHz], and the response sensitivity is 2.78 [mV/nT]. Data acquisition system with the resolution of 12 bits and memory capacity of 32 [Mbyte] was triggered by the magnetic field to be measured. The properties and parameters of the magnetic fields produced by cloud discharges were statistically investigated. The magnetic field waveforms radiated from cloud lighting discharges tend to be bipolar, with two or more narrow and several pulses superimposed on the initial front part. The recording length of the magnetic field measurement system is about 10 [ms]. The mean duration of cloud discharges is 1.3 [ms], and the number of outburst pulses for the period is 8 in average. The front times of the magnetic fields are 6.15 [$\mu$s] in average. The the zero-to-zero crossing times that is the initial half-cycle duration is widely dispersed and the mean value is 9.61 [$\mu$s], and the mean value of percentage depth of dip to opposite polarity is 41.1 [$\%$].

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.685-703
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• 2024

Cloud computing provides each consumer with a large-scale computing tool. Different Cyber Attacks can potentially target cloud computing systems, as most cloud computing systems offer services to many people who are not known to be trustworthy. Therefore, to protect that Virtual Machine from threats, a cloud computing system must incorporate some security monitoring framework. There is a tradeoff between the security level of the security system and the performance of the system in this scenario. If strong security is needed, then the service of stronger security using more rules or patterns is provided, since it needs much more computing resources. A new way of security system is introduced in this work in cloud environments to the VM on account of resources allocated to customers are ease. The main spike of Fog computing is part of the cloud server's work in the ongoing study tells the step-by-step cloud server to change the tremendous measurement of information because the endeavor apps are relocated to the cloud to keep the framework cost. The cloud server is devouring and changing a huge measure of information step by step to reduce complications. The Medical Data Health-Care (MDHC) records are stored in Cloud datacenters and Fog layer based on the guard intensity and the key is provoked for ingress the file. The monitoring center sustains the Activity Log, Risk Table, and Health Records. Cloud computing and Fog computing were combined in this paper to review data movement and safe information about MDHC.

• 한국멀티미디어학회논문지
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• 제17권2호
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• pp.152-159
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• 2014

최근 클라우드 컴퓨팅 기술의 발전에 따라 해저지도 데이터의 효율적인 측정, 기록 및 업데이트하는 분야에서의 원격탐사 기술과 클라우드 컴퓨팅 기술의 활용이 확대되고 있다. 실제 해양 분야에서 수심측정 및 측정 데이터 관리, 유통, 디스플레이 장비 개발 및 보급에 많은 시간과 비용이 발생하고 있다. 이러한 시스템을 개선하고자 실시간 3차원 디스플레이 시스템을 통하여 해당 위치에서의 측정 활동의 중요도를 판단할 수 있으며, 측정 활동의 시간과 비용 감소로 이어질 수 있다. 해양조사선 및 원격탐사 장비 등 다양한 경로를 통해 측정된 데이터는 클라우드 컴퓨팅 기술을 활용하여 처리, 관리된다. 본 논문에서는 원격탐사를 통한 수심측정과 동시에 실시간 3차원으로 디스플레이하는 시스템을 제안한다. 제안된 실시간 3차원 디스플레이 시스템은 해저지형뿐만 아니라 육지의 지형 측량 분야에서도 효과적으로 적용될 수 있다.

• 한국구조물진단유지관리공학회 논문집
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• 제27권5호
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• pp.84-88
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• 2023

최근 컴퓨터 비전, LiDAR 등을 활용하여 구조물의 유지관리를 효율화하기 위한 연구가 활발하게 이루어지고 있다. 건축물의 경우, 점검 항목 중 하나인 기울기는 일반적으로 토탈스테이션을 이용하여 계측하는데, 점검자에 따라 계측값이 일정하지 않아 정확한 기울기 값을 얻기 어렵다. 따라서, 본 연구에서는 현행 건축물 기울기 계측 방식의 신뢰도를 개선하고 측정 과정을 효율화하기 위하여 Point Cloud를 활용한 건축물 기울기 측정 자동화 방법론을 제안한다. 제안 방법론의 기울기 추정 알고리즘은 적용 대상을 직육면체 형태의 건물로 제한하며 외벽 평면 추출과 모서리 추정 및 기울기 계산의 두 단계로 이루어져 있다. 해당 알고리즘을 실제 건축물에 적용하여 기울기를 추정하였고, 이를 토탈스테이션을 이용한 계측방법과 비교하였다. 그 결과, 제안 기법은 정확도와 객관성, 그리고 자동화 관점에서 기존의 측정방식을 대체할 만한 수준으로 판단된다.