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Topic Review
Expenditures and Oscillation Analysis
The main purpose is to identify among variables that constitute water resources consumption at public schools, the link between consumption and expenditures oscillations. It was obtained a theoretical model of how oscillations patterns are originated and how time lengths have an important role over expenditures oscillations ergodicity and non-ergodicity.
  • 1.1K
  • 01 Nov 2020
Topic Review
Location-Aware Wi-Fi Authentication Scheme
Advanced wireless technology in Internet of Things (IoT) devices is increasing and facing various security threats. The authentication of IoT devices is the first line of defense for the wireless network. Especially in a Wi-Fi network, the existing authentication methods mainly use a password or digital certificate, these methods are inconvenient to manage due to certificate issuance or prone to be attacked because passwords are easily cracked. A location-aware authentication scheme was proposed, using smart contracts to ensure that IoT devices can securely perform Wi-Fi network authentication. The scheme adopts the concept of secondary authentication and consists of two phases: the registration phase, which is mainly designed to complete the generation of the public and private keys, and to link the device information with its related device information; the authentication phase, which is mainly designed to determine whether the requesting device is within a legal location range. The smart contract to ensure the credibility and irreparability of the authentication process. Analysis of the attack model and the attacks at different stages proves that this certification scheme is assured, and the simulation results show that the overhead introduced by this scheme is acceptable, this scheme can provide greater security for the Wi-Fi authentication of IoT devices.
  • 783
  • 01 Nov 2020
Topic Review
Walking Recognition in Mobile Devices
Presently, smartphones are used more and more for purposes that have nothing to do with phone calls or simple data transfers. One example is the recognition of human activity, which is relevant information for many applications in the domains of medical diagnosis, elderly assistance, indoor localization, and navigation. The information captured by the inertial sensors of the phone (accelerometer, gyroscope, and magnetometer) can be analyzed to determine the activity performed by the person who is carrying the device, in particular in the activity of walking. Nevertheless, the development of a standalone application able to detect the walking activity starting only from the data provided by these inertial sensors is a complex task. This complexity lies in the hardware disparity, noise on data, and mostly the many movements that the smartphone can experience and which have nothing to do with the physical displacement of the owner. In this work, we explore and compare several approaches for identifying the walking activity. We categorize them into two main groups: the first one uses features extracted from the inertial data, whereas the second one analyzes the characteristic shape of the time series made up of the sensors readings. Due to the lack of public datasets of inertial data from smartphones for the recognition of human activity under no constraints, we collected data from 77 different people who were not connected to this research. Using this dataset, which we published online, we performed an extensive experimental validation and comparison of our proposals.
  • 1.1K
  • 01 Nov 2020
Topic Review
Hunting Deeply Hidden Software Vulnerabilities
Fuzz testing is a simple automated software testing approach that discovers software vulnerabilities at a high level of performance by using randomly generated seeds. However, it is restrained by coverage and thus, there are chances of finding bugs entrenched in the deep execution paths of the program. To eliminate these limitations in mutational fuzzers, patching-based fuzzers and hybrid fuzzers have been proposed as groundbreaking advancements which combine two software testing approaches. Despite those methods having demonstrated high performance across different benchmarks such as DARPA CGC programs, they still present deficiencies in their ability to analyze deeper code branches and in bypassing the roadblocks checks (magic bytes, checksums) in real-world programs. In this research, we design DeepDiver, a novel transformational hybrid fuzzing tool that explores deeply hidden software vulnerabilities. Our approach tackles limitations exhibited by existing hybrid fuzzing frameworks, by negating roadblock checks (RC) in the program. By negating the RCs, the hybrid fuzzer can explore new execution paths to trigger bugs that are hidden in the abysmal depths of the binary. We combine AFL++ and concolic execution engine and leveraged the trace analyzer approach to construct the tree for each input to detect RCs. To demonstrate the efficiency of DeepDiver, we tested it with the LAVA-M dataset and eight large real-world programs. Overall, DeepDiver outperformed existing software testing tools, including the patching-based fuzzer and state-of-the-art hybrid fuzzing techniques. On average, DeepDiver discovered vulnerabilities 32.2% and 41.6% faster than QSYM and AFLFast respectively, and it accomplished in-depth code coverage.
  • 821
  • 30 Oct 2020
Topic Review
Digital Cloud Environment
This article addresses the challenges of a digital cloud environment when it comes to global scalability with a large number of remote servers and an unsecure public cloud, such as Amazon. The goal of the study was to work out an approach for evaluating the reasonable system capacity under heavy workload. For that purpose, Zabbix monitoring solution is used and business metrics are applied in relation to existing system ones. A prediction data model is proposed to compute the future forecast of the user activity based on the collected historical statistics and to verify whether capacity adjustment is possible or not. The results of capacity planning are implemented at Genesys International Telecommunications Company. System analysis of the production environment indicates the possibility to downscale the capacity of certain virtual servers, which allowed savings to the annual operational costs of $3500 (50%) for each affected server.
  • 1.2K
  • 30 Oct 2020
Topic Review
High-frequency analysis, Model Validation and Intraday risk metrics
Despite the growing amount of research in the field of high frequency financial data analysis, few studies have focused on model validation and high-frequency risk measures. This study contributes to the literature in the following ways: A rigorous model validation, both in terms of in-sample fit and out-sample performance for the MC-GARCH model under five error distributions is provided. Statistical and graphical tests are conducted to validate the models. One component of the MC-GARCH model is the daily variance forecast. For this purpose, the GARCH(1,1) and EGARCH(1,1) under the five error distributions are compared and the best model among the 10 GARCH models is used to forecast the daily variance. The modelling and forecasting performance of the MC-GARCH model under different distributional assumptions is assessed in this study. The 99% intraday VaR is forecasted and three backtesting procedures are used. This is the first study to assess the VaR predictive ability of the MC-GARCH models by using an asymmetric VaR loss function. This is the first study to forecast the intraday expected shortfall under different distributional assumptions for the MC-GARCH model. Again, three backtests are used including the recently proposed ES regression backtest. Due to the high importance of risk management, the results of this study may contribute in many fields. This study is highly relevant to the banking industry since banks are required to calculate risk metrics on a daily basis for internal control purposes and for determining their capital requirements. Risk measurement is also essential to the insurance industry from the pricing of insurance contracts to determining the Solvency Capital Requirement (SCR) and therefore the results of this study might be useful. Any other organisation having an exposure to some kind of financial risk might benefit from this study. 
  • 1.1K
  • 30 Oct 2020
Topic Review
Optimal Interpolation for infrared satellite data
Thermal infrared remote sensing measurements are blinded to surface emissions under cloudiness because infrared sensors cannot penetrate thick cloud layers. Therefore, surface and atmospheric parameters can be retrieved only in clear sky conditions giving origin to spatial fields flagged with missing pieces of information. Motivated by this we present a methodology to retrieve missing values of some interesting geophysical variables retrieved from spatially scattered infrared satellite observations in order to yield level 3 (L3), regularly gridded, data. The technique is based on a 2-Dimensional (2D) Optimal Interpolation (OI) scheme. The goodness of the approach has been tested on 15-min temporal resolution Spinning Enhanced Visible and Infrared Imager (SEVIRI) emissivity and surface temperature (ST) products over South Italy (land and sea), on Infrared Atmospheric Sounding Interferometer (IASI) atmospheric ammonia (NH3) concentration over North Italy and carbon monoxide (CO), sulfur dioxide (SO2) and NH3 concentrations over China. Sea surface temperature (SST) retrievals have been compared with gridded data from MODIS (Moderate-resolution Imaging Spectroradiometer) observations. For gases concentration, we have considered data from 3 different emission inventories, that is, Emissions Database for Global Atmospheric Research v3.4.2 (EDGARv3.4.2), the Regional Emission inventory in ASiav3.1 (REASv3.1) and MarcoPolov0.1, plus an independent study.
  • 783
  • 30 Oct 2020
Topic Review
English on EU Countries' Websites
The English language is the most dominant language in the western world and its influence can be noticed in every aspect of human communication. This article presents data about the prevalence of the English language in the different countries and regions of the European Union. By analyzing and processing the findings from over 100000 websites from every country in the EU, a solid foundation is set that is used to explore the dominance of the English language in the European World Wide Web in general. The results of this process demonstrate that the English language is not only available on more than one quarter of all websites of non-English speaking EU countries, but is also available in the vast majority of multilingual and bilingual websites of the EU, while at the same time being the only available language in a number of monolingual websites and shown preference over the national language in a significant number of cases.
  • 1.4K
  • 30 Oct 2020
Topic Review
Optical Sensor Networks
Optical sensing that integrates communication and sensing functions is playing a more and more important role in both military and civil applications. Incorporating optical sensing and optical communication, optical sensor networks (OSNs) that undertake the task of high-speed and large-capacity applications and sensing data transmissions have become an important communication infrastructure. However, multiple failures and disasters in OSNs can cause a serious sensing provisioning problem. To ensure uninterrupted sensing data transmission, the survivability has always been an important research emphasis. This paper focuses on the survivable deployment of OSNs against multiple failures and disasters. It first reviews and evaluates the existing survivability technologies developed for or that can be applied in OSNs, such as fiber bus protection, self-healing architecture, 1 + 1 protection, etc. Then, the disaster-resilient survivability requirement of OSNs is elaborated. Moreover, a new concept of k-node (edge) sensing connectivity, which ensures the connectivity between sensing data and users is proposed. Based on k-node (edge) sensing connectivity, the disaster-resilient survivability technologies are developed. The key technologies of implementing k-node (edge) sensing connectivity are also elaborated. Recently, artificial intelligence (AI) has obtained rapid development. It can be used to improve the survivability of OSNs. This paper also elaborates the potential development direction of survivability technologies of optical sensing in OSNs employing AI.
  • 1.5K
  • 30 Oct 2020
Topic Review
Human-Smart Environment Interactions
In the context of the challenges facing human computer interaction (HCI) on the one hand and the future Internet on the other, the purpose of this study is to explore the multi-dimensionality of smart cities, looking at relationships and interdependencies through correlating selected dimensions of smartness. Through a review of the research literature, key dimensions of smartness are identified for exploration in the context of smart cities in this work. Methodologically, this work combines an exploratory case study approach consisting of multiple methods of data collection including survey and in-depth interviews, with an explanatory correlational design. In terms of results, the main findings of this work shed light on relationships between selected dimensions of the multi-dimensionality construct of smartness in data-rich urban environments. This work is significant in that it provides correlational information for smart city dimensionalities while contributing to the research literature in this domain; uses a hybrid case study and correlational design in relation to the study of multi-dimensionality; and opens spaces for the study of innovative urban initiatives, taking the ideas and experiences of people from many sectors into consideration.
  • 811
  • 30 Oct 2020
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