Management Of Mobile Devices Research Articles

Forced convection heat transfer inside graphene aerogel

Ultralight heat-dissipating materials are essential for the effective thermal management of mobile devices. Graphene aerogel is a highly porous material made of thermally conductive carbon nanomaterial. Owing to aerogel's highly porous structure and graphene's high intrinsic thermal conductivity, graphene aerogel has a very low density and could be a promising ultralight thermal management material. In this study, forced convective heat transfer inside graphene aerogel is experimentally examined, and the effect of the aerogel microstructure on the heat and fluid flow characteristics of the graphene aerogel is discussed. It is established that graphene aerogel has a better convective heat transfer coefficient compared to conventional porous media. Furthermore, methods to improve the heat and fluid flow inside the aerogel are discussed. This work sheds light on the effective thermal management of various devices where lightness is critical.

Phase change microcapsules with graphene nanoplates embedded polyurea shell for enhanced thermal conductivity

• Graphene nanoplates (GNPs) as Pickering emulsifiers to stabilize n-docosane. • Regenerated nanochitin can combine with GNPs via the noncovalent interaction. • GNPs greatly enhances the thermal conductivity of microcapsules by 138%. • The microcapsules exhibit good thermal regulation capacity in electronic devices. Microencapsulated phase change materials with graphene nanoplates (GNPs) embedded polyurea shell and n-docosane (C 22 ) as core material were fabricated via Pickering emulsion polymerization. GNPs was used in combination with regenerated nanochitin as Pickering emulsifiers for enhanced stability due to mutual hydrophobic and electrostatic interactions. The microcapsules with 10 wt% GNPs (GNPs10/PU@C 22 ) exhibited melting enthalpy as high as 185.5 J/g and thermal conductivity as high as 0.65 W/m·K. GNPs10/PU@C 22 was also used to prepare composite films that showed great potential in thermal management of mobile phone devices.

Challenges for Cyber Security in the Use of Personal Devices at UNWE

The report explores the challenges of cybersecurity in the growing trend of "bring your own device" and the need for a policy for it. This policy is related to reducing the risk of using personal devices, such as smartphones, tablets and laptops when accessing, receiving or using data in the UNWE network. This is a complex area due to the presence of multiple users with different devices. The main problems are the increase in cyberattacks, data protection, access control and management of mobile devices. The purpose of the report is to provide guidelines for the implementation of a policy and procedure for the use of personal devices at UNWE, which will help preserve the confidentiality, integrity and availability of the university's formation assets.

Information security management of enterprise mobile device

The development of the modern labour market involves increasing the level of mobility of personnel, so the current trend is the spread of mobile devices in the implementation of professional activities. This practice improves the efficiency of enterprise, but also has a negative impact on the security of information systems of enterprises. The growing requirements of employers have led to the growth of the functionality of mobile devices. However, this also causes an increase in the number of vulnerabilities in them, leading to an increase in the complexity of the security processes. The combination of the above problems determines the need to organize the process of information security management of enterprise mobile devices. The model of information security management of enterprise mobile devices is described in the article. It allows identifying vulnerabilities of operating system objects of enterprise mobile devices by modelling combinations of dangerous permissions more accurately.

One-step scalable preparation of graphene nanosheets and high-thermal-conductivity flexible graphene films

It is well known that graphene nanosheets (GNSs) have many excellent properties. However, it has been a difficult thing to exfoliate graphite into GNSs in a controllable and scalable manner. In this research, a new strategy named xylitol-assisted ball milling exfoliation (XABME) was developed for the scalable preparation of GNSs. The experimental results characterized by a series of measurements showed that GNSs were successfully exfoliated by the XABME strategy. The structure of the prepared nanosheets was featured by large lateral size and ultra-small thickness. Furthermore, the prepared GNSs easily achieved high production yield (≈54%). Lastly, the as-obtained GNSs and cellulose nanofibers (CNF) were compounded to form some nanomaterial films. The prepared films exhibited excellent flexibility and higher thermal conductivity, with the in-plane thermal conductivity of 90 wt% GNS film (8.0 W/(m·K)) being 11.4 times higher than that of the film without GNSs. This shows that GNSs could effectively enhance the thermal conductivity of the CNF matrix and indicate that these prepared films have great potentials in the thermal management of portable mobile devices.

Simultaneously environmental-friendly exfoliation of boron nitride nanosheets and graphene and the preparation of high thermal conductivity nano-mixture composite membranes

Hexagonal boron nitride nanosheets (h-BNNS) and graphene (G) are considered to be the representative materials in the two-dimensional (2D) materials community. h-BNNS and G are considered to exhibit high potential in thermal management materials for their prominent thermal conductivity. However, the conventional methods to synthesize h-BNNS and G are restricted by several problems (e.g., high energy consumption, environmental pollution and complex preparation methods). In the present study, a xylitol (C5H12O5)-assisted ball milling method was developed for scalable synthesis of a 2D material mixture of h-BNNS and graphene (BNNS@G). With this method, about 52% yield could be achieved. Moreover, the produced mixture was re-dispersed; it also exhibited high stability in water. The method proposed in this study is capable of effectively transferring green chemistry solutions to the preparation. Besides, a green solution was also proposed to apply the synthesized BNNS@G. The as-obtained BNNS@G was mixed with the cellulose nanofiber solution to form a series of G@BNNS/CNF membranes that exhibited high flexibility and ultrahigh thermal conductivity. Furthermore, 70 wt% BNNS@G membrane (3.4 W/mK) exhibited the in-plane thermal conductivity 300% higher than the membrane without BNNS@G. Thus, it is suggested that the synthesized membranes exhibit high potentials in the thermal management of portable mobile devices.

Financial incentives for hypertension control: rationale and study design

BackgroundEven though the effectiveness of lifestyle modifications and antihypertensive pharmaceutical treatment for the prevention of hypertension and its complications have been demonstrated in randomized controlled trials, the benefits of adhering to these treatments have not been popularized among the general public. Studies suggest that incentive approaches based on behavioral economic concepts can improve patients’ adherence to treatment. Therefore, we aimed to test whether financial incentives will reduce the blood pressure (BP) of hypertensive patients in China.Methods/DesignThis is a multicenter, randomized controlled trial with two parallel arms. A total of 400 participants from six cities in the Liaoning and Shanxi provinces of China are block-randomized into intervention and control group with a 1:1 ratio. Patients in the control group will receive interactive management of mobile devices, including patient education and communication. Patients in the intervention group will receive financial incentives in addition to interactive management of mobile devices, conditional on them achieving their antihypertensive goals or hypertension control. Masking the arm allocation will be precluded by the behavioral nature of the intervention and investigators of BP measurement and statistics are masked to clinic assignment. The primary outcome is net change in systolic BP (SBP) from baseline to month 12 between the intervention and control groups. The secondary outcomes are net change in diastolic BP (DBP), BP control, change in medication adherence and lifestyle, and cost-effectiveness.DiscussionThis trial will determine whether financial incentives will improve hypertension control and generate necessary data for controlling hypertension and concomitant cardiovascular diseases among hypertensive patients in China.Trial registrationISRCTN13467677. Registered on 16 May 2019.

Adaptive multicast streaming for videoconferences on software-defined networks

Real-time applications, such as video conferences, have strong Quality of Service requirements for ensuring a decent Quality of Experience. Nowadays, most of these conferences are performed over wireless devices. Thus, an appropriate management of both heterogeneous mobile devices and network dynamics is necessary. Software Defined Networking enables the use of multicasting and stream layering inside the network nodes, two techniques able to enhance the quality of live video streams. In this paper, we propose two algorithms for building and maintaining multicast sessions in a software-defined network. The first algorithm sets up the initial multicast trees for a given call. It optimally places the stream layer adaptation function inside the core network in order to minimize the bandwidth consumption. This algorithm has two versions: the first one, based on shortest path trees is minimizing the latency, while the second one, based on spanning trees is minimizing the bandwidth consumption. The second algorithm adapts the multicast trees according to the network changes occurring during a call. It does not recompute the trees, but only relocates the stream layer adaptation functions. It requires very low computation at the controller, thus making our proposal fast and highly reactive. Extensive simulation results confirm the efficiency of our solution in terms of processing time and bandwidth savings compared to existing solutions such as multiple unicast connections, Multipoint Control Unit solutions and application layer multicast.

Users’ management of mobile devices and privacy

This article aims to offer a guide of observed practices based on the main results obtained after the two-year European Feder project (April 2013-15) ‘Public and private in mobile communications’ carried out at LabCom.IFP, Beira Interior University in Portugal. Both quantitative and qualitative methods were used (surveys, interviews, focus groups, content analysis, digital ethnography, observation ethnography, workshops, etc.) in order to describe how users manage their public, private, intimate and personal spheres within the mobile media ecosystem. Results obtained showed an increased awareness of the risks without a concomitant exploration of consequences, an extensively circumstantial behaviour pattern influenced by interface design and volatile policies, terms and conditions, and a lack of rational user behaviours and performances.

Experimental investigation of Phase Change Materials for thermal management of handheld devices

The trend of enhanced functionality and reducing size of mobile devices has led to a rapid increase in power density and a potential thermal bottleneck since thermal limits of components remain unchanged. Active cooling mechanisms are not feasible due to size, weight, and cost constraints. This work explores the feasibility of a passive cooling system based on Phase Change Materials (PCMs) for thermal management of mobile devices. The PCMs stabilize device temperatures due to the latent heat of phase change, thus increasing the operating time of the device before threshold temperatures are exceeded. The primary contribution of this work is the experimental evaluation of key parameters which influence the design of a PCM based thermal management system. In situ measurements with PCMs as a passive thermal management solution demonstrate that a significant extension in the time that the processor can run at full power before the processing power would need to be throttled to prevent damage.

MRM: mobile resource management scheme on mobile cloud computing

Mobile Resource Management without Cloud Server (MRM) is the computing resource integrated management of mobile devices in order to establish mobile cloud computing infrastructure without a cloud server and to provide computing services in this research. The MRM forms a logical resource pool to integrate physical resources from scattered mobile devices and provides computing services. In other words, the MRM offers static and dynamic performance-based computing services, designed to provide computing services that guarantee availability and expandability through a mobile device resource pool without a cloud server. To this end, the MRM defines static and dynamic metadata to manage mobile devices. Detailed schemes consisting of the MRM configuration, the MRM management, and the MRM operation are established to design and implement the MRM. To integrate the MRM resources and validate the effectiveness of the computing services, the configuration time for resource integration, and the task time, in accordance with simultaneous requests for computing services, is measured, and the availability results for the MRM are demonstrated.

모바일 IoT 디바이스 파워 관리의 체계적인 개발 방법: 휘처 기반 가변성 모델링 및 자산 개발

사물인터넷(IoT)은 다양한 디바이스가 유무선 네트워크를 통해 연결되어 정보를 수집, 처리, 교환, 공유하는 환경이다. 대표적 디바이스가 스마트폰 같은 모바일 IoT 디바이스인데, 사용자에게 고성능서비스를 제공하기 위해 파워를 많이 소비하지만 상시 공급할 수 없어서 주어진 IoT 환경에 적합하게 파워 관리를 하는 것이 필수적이다. 하지만 기존 모바일 IoT 디바이스의 파워 관리에는 AP, AP 내/외부 HW 모듈, OS, 플랫폼, 어플리케이션 등 다양한 요소가 복잡하게 얽혀 있어서 이 관계를 쉽게 파악하고 관리하는 체계적인 방법이 필요하다. 또한 파워 관리와 연관된 다양한 관리 정책, 운영 환경, 알고리즘 등 가변 요소를 분석하고 이를 파워 관리 개발에 반영하는 것이 필요하다. 본 논문에서는 이러한 문제점을 해결하고 모바일 IoT 디바이스 파워 관리를 체계적으로 개발하기 위한 공학 원칙과 이를 기반으로 한 방법을 제안한다. 실행가능성 검증을 위해 커넥티드 헬멧 시스템 파워 관리가 사례연구로 사용되었다.

Experimental and numerical study on phase change material (PCM) for thermal management of mobile devices

As mobile devices become more complex and higher in performance despite the smaller size, heat concentration at localized areas has become a problem. In recent years, passive cooling using phase change materials (PCMs) has drawn attention as a thermal management method for mobile devices. PCMs reduce the temperature increase rate due to their latent heat properties. This reduction in the temperature increase rate is called a “delay effect”. Moreover, microencapsulated PCMs (MPCMs) are attracting attention because they keep the melted PCMs from leaking. In this study, PCM sheets containing MPCM/polyethylene composite material are investigated for the thermal management of mobile devices. Namely the authors conduct a series of experiments using the PCM sheet with a high thermal conductivity sheet mounted into a simply modeled mobile device. Effects of the mass, the latent heat, the thermal conductivity, the configuration of the PCM sheet, and high thermal conductivity sheet on the temperature of a smart phone simulator are investigated. A finite element analysis (FEA) is also conducted considering the phase change of PCMs to investigate the optimal dimension and shape of PCMs. As a result, the delay effect of PCMs and the effectivity of a copper sheet pasted on the PCMs are verified by experiments. Moreover, FEA shows that using the PCM sheet with high thermal conductivity sheet has an advantage for the thermal management of mobile devices and gives an optimal condition for the PCM sheets.

파워 효율이 높은 모바일 IoT 단말 개발을 위한 소프트웨어 공학 원칙

An Internet of Things (IoT) is a system where various things are connected to each other via a wired/wireless network, and where information is gathered, processed, and interchanged/shared. One of the important actors in IoT is a mobile IoT device (such as a smartphone or tablet). These devices tend to consume a large amount of power in order to provide various high performance application services; however, as the devices cannot be supplied with power all the time, efficient power management is necessary. Power management of mobile IoT devices involves complex relationships between various entities such as application processors (APs), HW modules inside/outside AP, operating systems, mobile IoT platforms, and applications. In order to develop power-efficient mobile IoT devices, a method is needed to systematically analyze these relationships and manage power based on a clear understanding of them. To address this problem, software engineering principles for the development of power-efficient mobile IoT devices are presented in this paper. The feasibility of the proposed principles have been validated in the domain of smartphone camera power management.

Security Issues for Mobile Medical Imaging: A Primer.

The end-user of mobile device apps in the practice of clinical radiology should be aware of security measures that prevent unauthorized use of the device, including passcode policies, methods for dealing with failed login attempts, network manager-controllable passcode enforcement, and passcode enforcement for the protection of the mobile device itself. Protection of patient data must be in place that complies with the Health Insurance Portability and Accountability Act and U.S. Federal Information Processing Standards. Device security measures for data protection include methods for locally stored data encryption, hardware encryption, and the ability to locally and remotely clear data from the device. As these devices transfer information over both local wireless networks and public cell phone networks, wireless network security protocols, including wired equivalent privacy and Wi-Fi protected access, are important components in the chain of security. Specific virtual private network protocols, Secure Sockets Layer and related protocols (especially in the setting of hypertext transfer protocols), native apps, virtual desktops, and nonmedical commercial off-the-shelf apps require consideration in the transmission of medical data over both private and public networks. Enterprise security and management of both personal and enterprise mobile devices are discussed. Finally, specific standards for hardware and software platform security, including prevention of hardware tampering, protection from malicious software, and application authentication methods, are vital components in establishing a secure platform for the use of mobile devices in the medical field.

System Administration and Monitoring Moving Objects Using Mobile Devices

Paper presents a multiplatform server application for service management of mobile devices. Mobile devices can use as an alternative for surveillance and location in real-time taking the advantage of Global Positioning System (GPS) and wireless networks (Wi-Fi) technologies. We propose a monitoring system for personal safety it proposes since monitoring evidence in real-time and storage of multimedia files (image and video information).

IGreen: A ubiquitous dynamic network to enable manufacturer independent data exchange in future precision farming

In order to master the future challenges concerning increased demand for food and energy it is obvious that new methods are needed to boost productivity in a sustainable way. One key aspect to optimize agricultural processes and decision making is to derive effective means to acquire and share information along the value chain. In the past, data management in agriculture was dominated by proprietary, mostly Original Equipment Manufacturer (OEM) driven solutions with limited scope. To overcome the shortcomings associated with this, the German national joint research project iGreen was initiated in 2009 to enable convenient and efficient data sharing in a holistic and OEM independent way. As a project partner, John Deere focused on developing concepts and components for interconnecting machines among each other and with infrastructure nodes. In this paper the achieved results such as the infrastructure component referred to as the machine connector, the onboard data management and integration of mobile devices will be presented and evaluated through experiments focusing on data sharing in wheat and forage harvesting. The overall promising results indicate that in the future new applications focusing on optimizing processes can be enabled that will greatly improve the effectiveness and ease of agricultural production, especially fleet management and resource planning.

Context-Based Network Estimation for Energy-Efficient Ubiquitous Wireless Connectivity

Context information brings new opportunities for efficient and effective system resource management of mobile devices. In this work, we focus on the use of context information to achieve energy-efficient, ubiquitous wireless connectivity. Our field-collected data show that the energy cost of network interfaces poses a great challenge to ubiquitous connectivity, despite decent availability of cellular networks. We propose to leverage the complementary strengths of Wi-Fi and cellular interfaces by automatically selecting the most efficient one based on context information. We formulate the selection of wireless interfaces as a statistical decision problem. The challenge is to accurately estimate Wi-Fi network conditions without powering up the network interface. We explore the use of different context information, including time, history, cellular network conditions, and device motion, to statistically estimate Wi-Fi network conditions with negligible overhead. We evaluate several context-based algorithms for the estimation and prediction of current and future network conditions. Simulations using field-collected traces show that our network estimation algorithms can improve the average battery lifetime of a commercial mobile phone for an ECG reporting application by 40 percent, very close to the estimated theoretical upper bound of 42 percent. Furthermore, our most effective algorithm can predict Wi-Fi availability for one and ten hours into the future with 95 and 90 percent accuracy, respectively.

Thermal management of mobile devices

This paper presents the experimental study of using phase change material in the cooling of the mobile devices. It investigates the thermal performance of transient charging and discharging of mobile devices in three different situations; making phone calls frequently, making long duration calls, and making occasional calls. The results show that mobile devices are heated up fastest during the long duration usage. Experiments are also conducted to determine the effect of fins and effect of orientation of the mobile device on its thermal performance.