A Concurrent Testing Facility Approach to Validate Small Satellite Combined Operations

Federated remote laboratories allow for the execution of experiments ex situ. The coordination of several laboratories can be used to perform concurrent experiments of combined space operations. However, the latency of the communications between facilities is critical to performing adequate real-time experiments. This paper presents an approach for conducting coordinated experiments between floating platforms at two remote laboratories. Two independently designed platforms, one at Luleå University of Technology and the other at La Sapienza University of Rome, were established for this purpose. A synchronization method based on the Simple Network Time Protocol was created, allowing the offset and delay between the agents to be measured.Both platforms exchange data about their measured time and pose through a UDP/IP protocol over the internet. This approach was validated with the execution of simulated operations. A first demonstrative experiment was also performed showing the possibility to realize leader/follower coordinated operations. The results of the simulations and experiments showed communication delays on the order of tens of milliseconds with no significant impact on the control performance. Consequently, the suggested protocol was proven to be adequate for conducting coordinated experiments in real time between remote laboratories.

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A Low-Cost IoT System for Real-Time Monitoring of Climatic Variables and Photovoltaic Generation for Smart Grid Application

Sensors ◽

10.3390/s21093293 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3293

Author(s):

Gustavo Costa Gomes de Melo ◽

Igor Cavalcante Torres ◽

Ícaro Bezzera Queiroz de Araújo ◽

Davi Bibiano Brito ◽

Erick de Andrade Barboza

Keyword(s):

Real Time ◽

Renewable Resources ◽

Low Cost ◽

Photovoltaic System ◽

Meteorological Variables ◽

Data Set ◽

Photovoltaic Generation ◽

Network Time ◽

Network Time Protocol ◽

Continuous Current

Monitoring and data acquisition are essential to recognize the renewable resources available on-site, evaluate electrical conversion efficiency, detect failures, and optimize electrical production. Commercial monitoring systems for the photovoltaic system are generally expensive and closed for modifications. This work proposes a low-cost real-time internet of things system for micro and mini photovoltaic generation systems that can monitor continuous voltage, continuous current, alternating power, and seven meteorological variables. The proposed system measures all relevant meteorological variables and directly acquires photovoltaic generation data from the plant (not from the inverter). The system is implemented using open software, connects to the internet without cables, stores data locally and in the cloud, and uses the network time protocol to synchronize the devices’ clocks. To the best of our knowledge, no work reported in the literature presents these features altogether. Furthermore, experiments carried out with the proposed system showed good effectiveness and reliability. This system enables fog and cloud computing in a photovoltaic system, creating a time series measurements data set, enabling the future use of machine learning to create smart photovoltaic systems.

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Challenges in Time Transfer using the Network Time Protocol (NTP)

Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting ◽

10.33012/2017.14978 ◽

2017 ◽

Cited By ~ 3

Author(s):

Steven E. Sommars

Keyword(s):

Time Transfer ◽

Network Time ◽

Network Time Protocol

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Network time protocol performance evaluation in LAN environment

Journal of Computer Applications ◽

10.3724/sp.j.1087.2012.00943 ◽

2013 ◽

Vol 32 (4) ◽

pp. 943-945

Author(s):

Chao-fu CHEN ◽

Lei WANG

Keyword(s):

Performance Evaluation ◽

Network Time ◽

Protocol Performance ◽

Network Time Protocol

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Security Vulnerability Assessment of Google Home Connection with an Internet of Things Device

Proceedings ◽

10.3390/proceedings2021074001 ◽

2021 ◽

Vol 74 (1) ◽

pp. 1

Author(s):

Hilal Çepik ◽

Ömer Aydın ◽

Gökhan Dalkılıç

Keyword(s):

Internet Of Things ◽

Vulnerability Assessment ◽

Smart Home ◽

Human Life ◽

Computer Systems ◽

Security Vulnerability ◽

Network Time ◽

Network Time Protocol ◽

Home Systems

With virtual assistants, both changes and serious conveniences are provided in human life. For this reason, the use of virtual assistants is increasing. The virtual assistant software has started to be produced as separate devices as well as working on phones, tablets, and computer systems. Google Home is one of these devices. Google Home can work integrated with smart home systems and various Internet of Things devices. The security of these systems is an important issue. As a result of attackers taking over these systems, very serious problems may occur. It is very important to take the necessary actions to detect these problems and to take the necessary measures to prevent possible attacks. The purpose of this study is to test whether an attack that attackers can make to these systems via network time protocol will be successful or not. Accordingly, it has been tried to attack the wireless connection established between Google Home and an Internet of Things device over the network time protocol. Attack results have been shared.

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Real-Time Analysis Of In-Situ Spectroscopic Ellipsometric Data During Mbe Growth Of III-V Semiconductors

MRS Proceedings ◽

10.1557/proc-222-75 ◽

1991 ◽

Vol 222 ◽

Cited By ~ 10

Author(s):

B. Johs ◽

J. L. Edwards ◽

K. T. Shiralagi ◽

R. Droopad ◽

K. Y. Choi ◽

...

Keyword(s):

Real Time ◽

Optical Constants ◽

Growth Parameters ◽

Ex Situ ◽

Time Analysis ◽

Mbe Growth ◽

In Situ Data ◽

Real Time Analysis

ABSTRACTA modular spectroscopic ellipsometer, capable of both in-situ and ex-situ operation, has been used to measure important growth parameters of GaAs/AIGaAs structures. The ex-situ measurements provided layer thicknesses and compositions of the grown structures. In-situ ellipsometric measurements allowed the determination of growth rates, layer thicknesses, and high temperature optical constants. By performing a regression analysis of the in-situ data in real-time, the thickness and composition of an AIGaAs layer were extracted during the MBE growth of the structure.

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The feasibility and validity of using a real time location system (RTLS) to measure bedside contact time

Journal of Research in Nursing ◽

10.1177/17449871211016169 ◽

2021 ◽

pp. 174498712110161

Author(s):

Ann-Marie Cannaby ◽

Vanda Carter ◽

Thomas Hoe ◽

Stephenson Strobel ◽

Elena Ashtari Tafti ◽

...

Keyword(s):

Real Time ◽

Contact Time ◽

Measured Data ◽

Complete Agreement ◽

Observation Data ◽

The Real ◽

Measured Time ◽

The Difference ◽

Hospital Wards ◽

Location Systems

Background The association between the nurse-to-patient ratio and patient outcomes has been extensively investigated. Real time location systems have the potential capability of measuring the actual amount of bedside contact patients receive. Aims This study aimed to determine the feasibility and accuracy of real time location systems as a measure of the amount of contact time that nurses spent in the patients’ bed space. Methods An exploratory, observational, feasibility study was designed to compare the accuracy of data collection between manual observation performed by a researcher and real time location systems data capture capability. Four nurses participated in the study, which took place in 2019 on two hospital wards. They were observed by a researcher while carrying out their work activities for a total of 230 minutes. The amount of time the nurses spent in the patients’ bed space was recorded in 10-minute blocks of time and the real time location systems data were extracted for the same nurse at the time of observation. Data were then analysed for the level of agreement between the observed and the real time location systems measured data, descriptively and graphically using a kernel density and a scatter plot. Results The difference (in minutes) between researcher observed and real time location systems measured data for the 23, 10-minute observation blocks ranged from zero (complete agreement) to 5 minutes. The mean difference between the researcher observed and real time location systems time in the patients’ bed space was one minute (10% of the time). On average, real time location systems measured time in the bed space was longer than the researcher observed time. Conclusions There were good levels of agreement between researcher observation and real time location systems data of the time nurses spend at the bedside. This study confirms that it is feasible to use real time location systems as an accurate measure of the amount of time nurses spend at the patients’ bedside.

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NTP DRDoS Attack Vulnerability and Mitigation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.644-650.2875 ◽

2014 ◽

Vol 644-650 ◽

pp. 2875-2880

Author(s):

A. Alfraih Abdulaziz Nasser ◽

Wen Bo Chen

Keyword(s):

Amplification Factor ◽

Denial Of Service ◽

Personal Computers ◽

Distributed Network ◽

Network Time ◽

Hands On ◽

Time Zones ◽

Network Time Protocol ◽

The Way

The Network Time Protocol (NTP) is used to synchronize clocks of various computer devices such as personal computers, tablets, and phones based their set time zones. The network of devices that use these NTP servers form a huge distributed network that attracted a number of attacks from late 2013 towards early 2014. This paper presents a hands-on test of the Distributed Reflection Denial of Service (DRDoS) attack by the monlist command, provides more vulnerability in the protocol, and offers mitigation to these vulnerabilities. A Kali Linux server was used to test the monlist command on its localhost. The results showed that a request with a size of 234 bytes got a response of 4,680 bytes. A busy NTP server can return up to 600 addresses which were theoretically calculated to return approximately 48 kilobytes in 100 packets. Consequently, this results in an amplification factor of 206×. The knowledge of the way the attack can be propagated was an important step in thwarting the attack and mitigating more such threats in the same protocol.

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