Client Devices Research Articles

Use of a progressive web application for working with Earth remote sensing, topographic and cadastral data layers

This article proposes the use of the progressive web applications (PWA) for the geographic information systems’ (GIS) web user interfaces. The main advantages of this approach for GIS: use of arbitrary mobile and stationary devices; work in conditions of unstable connection to GIS server with fault-tolerant user input data delivery to the server, when the connection is restored; work offline with the information stored on client device, when the server is disconnected, and automatic synchronization of changed data, when the server connection is active; network traffic savings during data transfer. The above mentioned advantages are important for a number of practical applications in cadastral accounting and construction.

Secure Framework Enhancing AES Algorithm in Cloud Computing

The tremendous growth of computational clouds has attracted and enabled intensive computation on resource-constrained client devices. Predominantly, smart mobiles are enabled to deploy data and computational intensive applications by leveraging on the demand service model of remote data centres. However, outsourcing personal and confidential data to the remote data servers is challenging for the reason of new issues involved in data privacy and security. Therefore, the traditional advanced encryption standard (AES) algorithm needs to be enhanced in order to cope with the emerging security threats in the cloud environment. This research presents a framework with key features including enhanced security and owner’s data privacy. It modifies the 128 AES algorithm to increase the speed of the encryption process, 1000 blocks per second, by the double round key feature. However, traditionally, there is a single round key with 800 blocks per second. The proposed algorithm involves less power consumption, better load balancing, and enhanced trust and resource management on the network. The proposed framework includes deployment of AES with 16, 32, 64, and 128 plain text bytes. Simulation results are visualized in a way that depicts suitability of the algorithm while achieving particular quality attributes. Results show that the proposed framework minimizes energy consumption by 14.43%, network usage by 11.53%, and delay by 15.67%. Hence, the proposed framework enhances security, minimizes resource utilization, and reduces delay while deploying services of computational clouds.

Plant Spike: A Low-Cost, Low-Power Beacon for Smart City Soil Health Monitoring

Plant Spike is an in situ low-cost sensor system that is wireless, miniature, and low powered. It can be seamlessly implanted in subsurface locations across major cities to measure urban soil health. Plant Spike incorporates noncontact soil moisture monitoring, temperature monitoring, light intensity monitoring, advanced power management, and Bluetooth low energy transmit-only communication for transmitting information to a client device. With a novel combination of aggressive power reduction techniques, the system’s lifetime is over two years with a 500-mAh battery. By connecting on-board sensors to a single-chip microcontroller, the total component and assembly cost of each module is less than $10. The sensor system has been tested within an urban soil testbed located on Columbia University’s Morningside Campus in New York City as well as street tree pits located in Morningside Heights, proving the functionality and robustness of the system. Plant Spike is able to measure temperature and light ranges that are comparable to the fluctuations experienced by soils located within the climate zone of New York City.

Indoor Positioning System Based on Fuzzy Logic and WLAN Infrastructure.

This paper deals with the issue of mobile device localization in the environment of buildings, which is suitable for use in healthcare or crisis management. The developed localization system is based on wireless Local Area Network (LAN) infrastructure (commonly referred to as Wi-Fi), evaluating signal strength from different access points, using the fingerprinting method for localization. The most serious problems consist in multipath signal propagation and the different sensitivities (calibration) of Wi-Fi adapters installed in different mobile devices. To solve these issues, an algorithm based on fuzzy logic is proposed to optimize the localization performance. The localization system consists of five elements, which are mobile applications for Android OS, a fuzzy derivation model, and a web surveillance environment for displaying the localization results. All of these elements use a database and shared storage on a virtualized server running Ubuntu. The developed system is implemented in Java for Android-based mobile devices and successfully tested. The average accuracy is satisfactory for determining the position of a client device on the level of rooms.

Spreading distinctive insignia benefits from mobile service: evidence from a mobile application of transportation

ABSTRACT Mobile commerce (m-commerce) faces a growing array of client devices for which applications are designed. Applications developed for general consumer use must be compatible with a wide range of devices. This research investigates how perceived usefulness and enjoyment affect intention to use a mobile application service (T-Express). In this study, we formulate a commitment model from the perspective of the social identity and technology acceptance perspective. Empirical data were collected by conducting a field survey of users of T-Express from Taiwan High Speed Rail Corporation (THSRC) stations in Taiwan. The main findings of the study are that wireless technology provides great value to businesses when it allows consumers to access real-time data to make timely decisions that either decrease costs or increase revenues; and to achieve a higher intention to use mobile applications, there should be a clear communication process between mobile application and passenger. Our findings indicate that one of the more overt illustrations of the power of packaging symbolism involves package design strategies that serve to provide a radical new upscale positioning for the THSRC brand.

Efficient Scheduling, Caching, and Merging of Notifications to Save Message Costs in IoT Networks Using CoAP

Internet-of-Things (IoT) devices are widely deployed and many of them have limited capabilities. Constrained application protocol (CoAP) is developed to integrate such devices into the Web environment. Specifically, client devices register their interested data with IoT devices, which will keep notifying them of the status of sensing data. However, client devices have different demands in terms of minimum and maximum periods to receive notifications, whereas IoT devices usually offer notifications at regular intervals. Some IoT devices would send many more notifications than necessary, which wastes bandwidth and energy. To conquer this problem, this article proposes a group-based message management (GMM) framework for CoAP proxies to efficiently coordinate the sending of notifications from IoT devices and forward them to client devices. GMM curtails superfluous notifications by three modules. The scheduling module groups client devices based on their demands and finds an optimal observation period for each group. The caching module adjusts the max-age value to allow a proxy reusing its cached notifications to answer requests. The merging module combines the notifications originated from different IoT devices queried by the same client device so as to save bandwidth. The simulation results show that GMM not only reduces unnecessary notifications but also conserves the energy of devices.

The Dataset of the Experimental Evaluation of Software Components for Application Design Selection Directed by the Artificial Bee Colony Algorithm

The paper presents the swarm intelligence approach to the selection of a set of software components based on computational experiments simulating the desired operating conditions of the software system being developed. A mathematical model is constructed, aimed at the effective selection of components from the available alternative options using the artificial bee colony algorithm. The model and process of component selection are introduced and applied to the case of selecting Node.js components for the development of a digital platform. The aim of the development of the platform is to facilitate countrywide simultaneous online psychological surveys in schools in the conditions of unstable internet connection and the large variety of desktop and mobile client devices, running different operating systems and browsers. The module whose development is considered in the paper should provide functionality for the archiving and checksum verification of the survey forms and graphical data. With the swarm intelligence approach proposed in the paper, the effective set of components was identified through a directional search based on fuzzy assessment of the three experimental quality indicators. To simulate the desired operating conditions and to guarantee the reproducibility of the experiments, the virtual infrastructure was configured. The application of swarm intelligence led to reproducible results for component selection after 312 experiments instead of the 1080 experiments needed by the exhaustive search algorithm. The suggested approach can be widely used for the effective selection of software components for distributed systems operating in the given conditions at this stage of their development.

Efficiency increase in the 802.11 Ac standard performance due to the influence of Airtime Fairness technology

The article considers one of the critical problems of wireless network performance, namely, monopolization of airtime by slow clients.The advantages of wireless Wi-Fi technology are considered. The main versions of Wi-Fi standards are analyzed. It is shown that a wide variety of Wi-Fi standards is aimed at improving network performance indicators, which is expressed in increasing the transmission speed, optimizing the use of frequency bands, increasing the efficiency of Wi-Fi in segments with high subscriber density, as well as in the possibility of multiple streaming of high definition video.The IEEE 802.11ac standard is analyzed. The choice of 802.11 ac technology is based on its availability and flexibility. It is indicated that the main problem point of this standard is the inconvenience of its performance under strong differentiation of client devices, which is reflected in a decrease in network bandwidth as a whole.The network performance using Airtime Fairness technology is analyzed. To solve the problem of monopolization of airtime by slow clients, the cyclic method of dividing airtime into given intervals has been used. The necessary equipment, hardware and initial conditions for the study are indicated. It is shown that the network efficiency is determined by the following productivity indicators: average packet productivity, average bandwidth and wireless channel utilization.It has been explained that with changes in system settings due to activation of Airtime Fairness technology algorithms, there is an increase in packet productivity and average bandwidth, as well as a decrease in the utilization rate of the wireless channel, which proves the presence of positive changes in the wireless network.

OPAIEH: An Ontology-based Platform for Activity Identification of the Elderly at Home

Recently, the sector of the population older than 60 years of age is growing. The assistance for the elderly at their home allows to increase their autonomy and independence while they are living alone. Several fields have emerged to improve the quality of life of the elderly, and to develop environments that offer help, support and assistance during the realization of their daily activities. The identification of activities is a key piece for the provision of assistance to seniors who live alone. This work is focused on the activity recognition of the elderly who live independently at home. Here is presented OPAIEH, an ontology-based platform for activity identification of the elderly at home. The platform includes the ontological model, which allows a new activity characterization. Also, the platform includes a sensors network, a client device, and web server to perform the recognition of different activities that the elderly do inside their home. Furthermore, the platform generates a set of graphs that shows different statistics and behaviours of the users. In order toper form an experimental test on OPAIEH, a case study was developed as a proof of concept about the use of ontologies for the activity recognition task. The results encourages us to continue our work.

Performance Evaluation of TCP Data Transmission in 5G mmWave Networks

Abstract—Fifth generation (5G) networks should use millimeter-wave (mmWave) frequencies to provide high data transmission rate. However, the performance of such networks significantly suffers from the Transmission Control Protocol (TCP) used by various applications for data transmission. In this article, it is shown that the data download rate in 5G networks is much lower than the capacity of the mmWave link because of the Slow Start algorithm used in the TCP. We analyze various approaches to the problem and propose to use the xStream platform for adjusting TCP parameters. This approach significantly increases the download rate and does not require any changes to the software of client devices, which simplifies the implementation of the proposed approach in real systems.

A Low-Resolution IR-Array as a Doorway Occupancy Counter in a Smart Building

A doorway counter, which detects a person underpass at a room entry/exit, may be the most accurate type of occupancy counters used in buildings. An occupancy counter, which uses a low-resolution IR-imager and Raspberry Pi board has been constructed. The imager provides only 8 x 8 pixels initial resolution, but it has been enhanced using two-dimensional interpolation. Due to the low absolute accuracy in temperature measurements, the imager is set to measure temperature difference between a target and background. Signal-to-noise ratio is also increased using discrete two-dimensional convolution filtering. The blob detection and tracking algorithm deduces the direction of an occupant and finally increments or decrements the counter. A heat signature varies between people and depends on person’s clothing. An on-board server on Raspberry Pi distributes the data via Wi-Fi to any client device in the net. The complete system includes also wireless PIR-sensors. The low-resolution IR occupancy counter has been compared with counters based on different technologies. The benefits of a low-resolution IR-imager are privacy preservation, operation capability in total darkness, energy-efficient passive operation and a low price.

Association stability and handoff latency tradeoff in dense IEEE 802.11 networks: A case study

Association instability is a common phenomenon in dense networks. The decision of whether or not to perform a handoff between access points in an infrastructured IEEE 802.11 network is taken exclusively by the wireless client stations. Even without mobility, static client devices may decide to migrate to another access point with the goal of improving performance. However, the criteria used to perform handoffs are not defined by the IEEE 802.11 standard and, thus, are dependent on specific vendor implementations. In this paper, we use data from a real large scale network and run experiments to demonstrate that such implementations are commonly deficient, resulting in high levels of association instability in dense environments. By analyzing the implementation used by the most common devices and conducting comparative tests in a real network, we were able to conclude that this instability, known as the “ping-pong effect”, results from the direct usage of RSSI samples which are highly variable. Also, we conclude that, despite being effective, common solutions for the ping-pong effect can cause additional delay to the handoff process, which is undesirable. Finally, we analyze the behavior of RSSI in indoor environments showing that its time series presents multimodal distribution. We argue that the findings presented in this study can help develop more stable handoff algorithms for dense wireless networks.

Energy-Efficient Video Processing for Virtual Reality

Virtual reality (VR) has huge potential to enable radically new applications, behind which spherical panoramic video processing is one of the backbone techniques. However, current VR systems reuse the techniques designed for processing conventional planar videos, resulting in significant energy inefficiencies. Our characterizations show that operations that are unique to processing 360° VR content constitute 40% of the total processing energy consumption. We present EVR, an end-to-end system for energy-efficient VR video processing. EVR recognizes that the major contributor to the VR tax is the projective transformation (PT) operations. EVR mitigates the overhead of PT through two key techniques: semantic-aware streaming on the server and hardware-accelerated rendering on the client device. Real system measurements show that EVR reduces the energy of VR rendering by up to 58%, which translates to up to 42% energy saving for VR devices.

ВЕБ ОРІЄНТОВАНА СИСТЕМА ДОСТУПУ ДО ВІДДАЛЕНОГО РОБОЧОГО СТОЛУ ТА ПРОГРАМНОГО КОМПЛЕКСУ GRAN У ПРОЦЕСІ НАВЧАННЯ МАТЕМАТИКИ В ШКОЛІ

The article deals with Gran software and the access to it through the remote desktop. The peculiarities of web-based remote desktop access and Gran software system for teaching mathematics at school are revealed. The paper also describes the application of open source software (Ulteo OVD) that allows users to remotely access their desktops and applications using one of the Desktop as a Service cloud components through a client device browser. The modes of using Ulteo OVD client software are described. Two servers (Application Server and Session Manager Server) have been organized to use Ulteo OVD by means of PROXMOX web-based virtual environment. The authors propose the way to use Ulteo OVD to access software installed on a remote server, in particular Gran software. The article also describes some examples of graphical problem solving using Gran1 that can be used in maths at school. The considered issues are quite complex and rather time-consuming without Gran1 software for graphical analysis of various tasks and approximate calculation of numerical measures of different objects (lengths of surfaces, areas of surfaces, volumes of bodies, probabilities of occurrence of different events, statistical analysis of observational data) of their solving. The range of tasks that can be solved with the use of the Gran software package, in particular Gran1 programme, is quite broad. By applying a creative approach, their analysis and solution can have a positive effect on the learners’ mental and cultural development. It is emphasized that the use of various technologies in educational process, as well as the selection of tasks and the content of training in general, should be pedagogically weighted, based on the harmonious combination of pedagogical heritage of the past and modern achievements of scientific and technological progress.

Development of Cloud of Things Based on Proxy Using OCF IoTivity and MQTT for P2P Internetworking

In recent years, the development of Cloud and Internet of Things (IoT) integrated applications are becoming more and more popular among developers, and this combined system is described as Cloud of Things (CoT). Cloud of Things can be utilized for finding optimal solutions for various problems. CoT is one of the essential methods for the construction and development of smart cities. With the installation of CoT based technologies, people can be able to check, control environmental parameters through intelligent embedded devices. In this paper, we present a CoTarchitecture based on proxy using Peer to Peer (P2P) connectivity for interworking IoT devices and Cloud. Proposed Cloud of Things architecture supports IoT devices’ contextual data transformation to the Cloud-based on P2P connectivity using Open Connectivity Foundation (OCF) IoTivity and Message Queuing Telemetry Transport (MQTT) protocol. The proposed system provides a collection of huge sensing information via Internet of Things devices and upload gathered data to Cloud for further analyzation. The proxy can acquire sensor data from the Internet of Things networks and then publish the data as messages to the subject in Internet of Things global Cloud. Moreover, this Cloud of Things architecture supports the peer to peer internetworking for communication of client devices and embedded devices. Finally, we also compared the IoT service of global Cloud platforms in CoT experiments.

RDSP: Rapidly Deployable Wireless Ad Hoc System for Post-Disaster Management.

In post-disaster scenarios, such as after floods, earthquakes, and in war zones, the cellular communication infrastructure may be destroyed or seriously disrupted. In such emergency scenarios, it becomes very important for first aid responders to communicate with other rescue teams in order to provide feedback to both the central office and the disaster survivors. To address this issue, rapidly deployable systems are required to re-establish connectivity and assist users and first responders in the region of incident. In this work, we describe the design, implementation, and evaluation of a rapidly deployable system for first response applications in post-disaster situations, named RDSP. The proposed system helps early rescue responders and victims by sharing their location information to remotely located servers by utilizing a novel routing scheme. This novel routing scheme consists of the Dynamic ID Assignment (DIA) algorithm and the Minimum Maximum Neighbor (MMN) algorithm. The DIA algorithm is used by relay devices to dynamically select their IDs on the basis of all the available IDs of networks. Whereas, the MMN algorithm is used by the client and relay devices to dynamically select their next neighbor relays for the transmission of messages. The RDSP contains three devices; the client device sends the victim’s location information to the server, the relay device relays information between client and server device, the server device receives messages from the client device to alert the rescue team. We deployed and evaluated our system in the outdoor environment of the university campus. The experimental results show that the RDSP system reduces the message delivery delay and improves the message delivery ratio with lower communication overhead.

Hardware Acceleration for Container Migration on Resource-Constrained Platforms

The computing capabilities of client devices are continuously increasing; at the same time, demands for ultra-low latency (ULL) services are increasing. These ULL services can be provided by migrating some micro-service container computations from the cloud and multi-access edge computing (MEC) to the client devices. The migration of a container image requires compression and decompression, which are computationally demanding. We quantitatively examine the hardware acceleration of container image compression and decompression on a client device. Specifically, we compare the Intel® Quick Assist Technology (QAT) hardware acceleration with software compression/decompression. For scenarios with a local container image registry (i.e., without network bandwidth constraints), we find that Intel QAT speeds up compression by a factor of over 7 compared to the single-core GZIP software and reduces the CPU core utilization by over 15% for large container images. These Intel QAT benefits come at the expense of Input/Output (IO) memory access bitrates of up to 900 Mbyte/s (while the software compression/decompression does not require IO memory access). For scenarios with a remote container image registry, we find that the container push (compression) time savings increase with the network bandwidth, while the container pull (decompression) time savings level out for moderately high network bandwidths and slightly decrease for a very high network bandwidth. Furthermore, Intel QAT acceleration achieves substantial power consumption reductions for container push compression for low to moderately high network bandwidths. Our evaluation results give reference performance benchmarks of the achievable latencies for container image instantiation and migration with and without hardware acceleration of the compression and decompression of container images.

Formal Verification of Secure Evidence Collection Protocol using BAN Logic and AVISPA

The effect of digitization has led to an increased dependency on the internet. At the same time, cyber-attacks are on the rise due to this increased digitization. In cybercrime cases, digital evidence is of utmost importance. The forensic investigation process always begins after the incident occurred, by that time intelligent attackers got enough time to destroy the traces. This paper proposes a prior evidence capture protocol, that will help in the simultaneous collection of evidence when the crime has occurred. This collected evidence is in the form of device fingerprint which will uniquely identify the fingeprintee client device. In the future, if the dispute arises these prior captured device fingerprints can be used as legal evidence and help in the process of forensic investigation. The proposed protocol uses the concept of a trusted time stamping server (TTSS) to prove the integrity and non-repudiation of the collected evidence. The timestamps are attached by the trusted third party TTSS with all collected evidence, these timestamps cannot be changed by local client devices. The paper also provides security validation of the proposed protocol by using Burrows–Abadi–Needham (BAN) logic. The formal verification is also done by using the AVISPA tool. The results of AVISPA shows that the proposed protocol is safe under OFMC and Cl-AtSe model.

Design and Implementation of Bitrate Adaptation Schemes for Power Capping in Wi-Fi Video Streaming

In dynamically adaptive streaming over HTTP (DASH), which is the de facto standard for streaming, each video is divided into segments, and each segment is further transcoded into multiple bitrate versions. This allows a client device to select the most appropriate bitrate version that matches the network bandwidth to avoid jitters or stalls. However, Wi-Fi download of a high-bitrate version may consume significant energy, especially when network conditions are good. To address this, we propose a new streaming method that limits the energy consumed by mobile devices but maintains an acceptable video quality. First, we derive a power model to analyze how bitrate selection affects power consumption in smartphones. Based on this, we propose two algorithms that determine the bitrate of each segment with the aim of maximizing overall video quality while limiting energy consumption. We use dynamic programming and heuristics to address the tradeoff between algorithm complexity and video quality. The proposed scheme was implemented on an Android-based DASH streaming platform, and various issues were resolved to cope with varying network conditions. Experimental results demonstrated that our scheme effectively optimized the video quality while limiting the energy consumption. For example: 1) our scheme uses 4% and 10% less power than DASH while maintaining an excellent video quality, and 2) the average difference between estimated and actual power consumption is 0.8%, thus keeping a precise energy bound.

Topological Data Models for Virtual Management of Hidden Facilities Through Digital Reality

The integral management of facilities located in the subsoil or hidden in walls and ceilings entails numerous challenges in terms of accurate positioning and data update. We describe the characteristics of the information system designed to act in the life cycle of facilities networks. We focus on the data model design, whose core connects topologically the 3D geometric objects representing facilities components. This scheme enables CRUD (Create, Read, Update, Delete) operations directly on the 3D objects of the digital reality, and through desktop or mobile devices. The system is implemented in a client-server architecture. The server maintains the complete topological data model in a spatial database. This model is redesigned and replicated in the memory of any client device with graphical capabilities. Conventional computers can enable Virtual Reality, while mobile devices can access ubiquitously surrounding facilities through Augmented Reality. In addition, the design of a third data model allows the exchange of this information using a standard format such as CityGML. Current facilities networks have been used to test the CRUD operations functionality.