Kinds Of Terminals Research Articles

Real Time Implementation of Terminal Security Policies Selection Based on Edge Computing

There are many kinds of terminals in the smart grid system, which have different functions and risks in the system. Different security policies are needed to protect the terminals. At the same time, the terminals will be subject to various attacks in operation. These attacks will change the security protection performance of terminals. Therefore, it is necessary to adjust the security policies in their operation. This paper proposes a real-time implementation method of terminal security policy selection under the edge computing based on the machine learning methods, which makes full use of the computing power of edge devices, adopts offline training and online judgment. The training of machine learning parameters can be completed in the edge side or in the cloud while the security strategies selection continues going on the edge computing side. By this way, the real-time training update and real-time selection of security policy in edge computing system are realized.

BTNC: A blockchain based trusted network connection protocol in IoT

Along with the rapid growth of the size and complexity of Internet of Things (IoT), the security of terminal devices has increasingly become a focus. In order to ensure the security of terminals, the trusted network connect (TNC) could realize not only the user authentication but also the platform attestation during the network access process. However, the existing TNC infrastructure is based on a centralized architecture, which is not suitable for distributed services. To address this problem, we present a blockchain-based TNC protocol named BTNC to ensure the reliability of terminals in IoT. Due to the decentralization, trustlessness, trackability, and immutability features of blockchain, BTNC is able to verify the security of terminal devices in IoT networks. First, we come up with some threats, including unauthorized user, illegal platform and platform replacement attack, then correspondingly define the security goals of our scheme. Second, combining key exchange protocol based on blockchain and D–H PN protocol included in TNC specification, we propose a blockchain-based trusted network connection protocol, which realizes mutual user authentication, platform attestation and trust network access by cryptography among terminals in IoT. Third, we make a security analysis in the PCL mode and conclude that our protocol can resist the attacks above. Finally, the performance overheads caused by our scheme are evaluated and the experiments show that it is efficient and feasible for different kinds of terminals in IoT.

Guest Editorial Special Issue on Spectrum and Energy Efficient Communications for Internet of Things

The Internet of Things (IoT) provides enormous connections of devices and sensors with different applications. It is an enabling technology for smart city, intelligent transportation systems, environmental monitoring, security surveillance, smart homes, satellite and space information network, ocean monitoring, and unmanned border awareness systems, just to name a few. IoT as a high-density network will take the burden of massive data generated by different kinds of terminals and sensors. Dramatic growth in IoT has created a shortage in the available radio spectrum. Wireless communications services in IoT such as cellular phones, tablets, and wireless Internet access have to compete with existing users in radar, government and military communications, environmental monitoring, and other IoT applications. The strategy to increase the efficiency of spectrum sharing among the enormous users in IoT. Besides, the IoT applications demand more and better functionality and performance from new electronic devices; these demands translate into greater energy consumption demands. The gap between energy storage and demand continues to grow and the battery technologies for energy storage are not expected to increase tremendously in the coming years. Furthermore, reducing signal transmission power can lessen interference among devices in IoT. Energy-efficient protocols and network architectures will further reduce the number of transmissions and extend the battery life of IoT devices (IoTDs). Therefore, it is essential to pursue fundamental research on new components, techniques, and architectures to achieve energy-efficient sensing, communications, and networking in a shared spectrum environment for IoT.

An effective heteroatom-substituted strategy on photovoltaic properties of D(A-Ar)2 small molecules for efficient organic solar cells

To research the effects of different kinds of terminals on the solar cell performance, in this paper, carbazole (Cz), 2-octylthiophene (T) and 2-octylhiothiophene (TS) units are picked as end-capping units, with a pyran-bridged indacenodithiophene (IDTP) as central core and two fluorinated benzothiadiazole (DFBT) as acceptors, three π-conjugated small molecules (SMs) with D(A-Ar)2 framework, namely IDTP(DFBT-Cz)2, IDTP(DFBT-T)2 and IDTP(DFBT-TS)2, respectively, were designed and synthesized for application as donor materials in solution-processed small molecular organic solar cells (SM-OSCs). Encouragingly, after the tetrahydrofuran (THF) solvent vapor annealing (SVA) process, the device based on IDTP(DFBT-TS)2 exhibited outstanding efficiencies up to 7.33%, which is 1.71 times equal to the 4.29% PCE of the alkyl terminal substitution IDTP(DFBT-T)2, and 1.45 times equal to the 5.06% PCE of the carbazolyl terminal substitution IDTP(DFBT-Cz)2, which is mainly attributed from its better molecular planarity, higher hole mobility, and better morphologies of blend films in comparison with the other two SMs. To our best knowledge, this work with the IDTP core in SM donor materials is reported for the first time, compared to the IDT core, the IDTP core proved to effectively improve molecular crystallinity and fill factor (FF). The results reported here clearly demonstrate that the alkylthio substitution terminal-group engineering is an effective strategy to further improve the photovoltaic performance of the molecules.

Wideband Single-Ended and Differential Bandpass Filters Based on Terminated Coupled Line Structures

In this paper, a novel terminated coupled line structure (TCLS) is introduced, which is constructed by a coupled line section and four terminations loaded on it. Introducing different kinds of terminations, three types of bandpass filters (BPFs) based on TCLSs are proposed, theoretically analyzed, and fabricated, including two single-ended wideband BPFs with fractional bandwidths (FBWs) of 67% and 40% respectively, and a wideband differential BPF with 74% differential-mode FBW. These BPFs can achieve wide passband bandwidth, low in-band insertion loss, high passband selectivity, as well as deep stopband rejection performance simultaneously, benefited from the multiple transmission zeros and transmission poles obtained by the TCLSs. The practical design procedures of these BPFs are presented and explained. The agreement among theoretical predictions, EM-simulated, and measured results validates our proposed filter structures. Finally, the generalized multistage filter topology based on TCLSs is proposed to design high-order filters with better filtering performances.

Waveform Design for 5G Networks: Analysis and Comparison

The next-generation cellular network is to provide a large variety of services for different kinds of terminals, from traditional voice and data services over mobile phones to small packet transmission over massive machine-type terminals. Although orthogonal-subcarrier-based waveforms are widely used nowadays in many practical systems, they can hardly meet the requirements in the coming 5G networks. Therefore, more flexible waveforms have been proposed to address the unprecedented challenges. In this paper, we will provide comprehensive analysis and comparison for typical waveforms. To offer an insightful analysis, we will not only introduce the basic principles of the waveforms, but also reveal the underlying characteristics. Moreover, a comprehensive comparison in terms of different performance metrics will also be presented in thispaper, which provides an overall understanding of the new waveforms.

Experimental study on the 4H-SiC-based VDMOSFETs with lightly doped P-well field-limiting rings termination

A lightly doped P-well field-limiting rings (FLRs) termination on 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors (VDMOSFETs) has been investigated. Based on the simulation, the proposed termination applied to 4H-SiC VDMOSFET could achieve an almost same breakdown voltage (BV) and have the advantage of lower ion-implantation damage comparing with P+ FLRs termination. Meanwhile, this kind of termination also reduces the difficulty and consumption of fabrication process. 4H-SiC VDMOSFETs with lightly doped P-well (FLRs) termination have been fabricated on 10μm thick epi-layer with nitrogen doping concentration of 6.2×1015cm−3. The maximum breakdown voltage of the 4H-SiC VDMOSFETs has achieved as high as 1610V at a current of 15μA, which is very close to the simulated result of 1643V and about 90% of the plane parallel breakdown voltage of 1780V. It is considered that P-well FLRs termination is an effective, robust and process-tolerant termination structure suitable for 4H-SiC VDMOSFET.

First-principles study of the cubic CaHfO3(001) surface

The geometric and electronic structures of the cubic CaHfO3(001) surfaces have been studied using first-principles density functional theory (DFT) calculations. Two different terminations, CaO- and HfO2-terminated surfaces, were investigated. It has been found that Ca atom has the largest relaxation for both kinds of terminations, and the surface rumpling of the CaO termination is far more prominent than that of the HfO2-terminated surface. Both the bandgaps of the CaO- and HfO2-terminated surfaces were calculated to be smaller than that of the CaHfO3bulk. It was also shown that the CaO-terminated surface has a lower energy than the HfO2-terminated surface.

Ab initio investigation of the adsorption of zoledronic acid molecule on hydroxyapatite (001) surface: an atomistic insight of bone protection

We report a computational study of the adsorption of zoledronic acid molecule on hydroxyapatite (001) surface within ab initio density functional theory. The systematic study has been performed, from hydroxyapatite bulk and surface, and zoledronic acid molecule to the adsorption of the molecule on the surface. The optimized bond lengths and bond angles were obtained and analyzed, giving an evidence of structural similarity between subjects under study. The formation energies of hydroxyapatite (001) surfaces with two kinds of terminations were computed as about 1.2 and 1.5 J/m^2 with detailed atomistic structural information. We determined the adsorption energies of zoledronic acid molecule on the surfaces, which are -260 kJ/mol at 0.25 ML and -400 kJ/mol at 0.5 ML. An atomistic insight of strong binding affinity of zoledronic acid to the hydroxyapatite surface was given and discussed.

Development and performances of standalone visible light communication terminals using imitate infrared encoding technique

By introducing the imitate infrared encoding technique and employing a white light emitting diode (WLED), a pair of standalone visible light communication (VLC) terminals, including a transmitter and a receiver, were experimentally demonstrated. The mathematic modelling and formulation were proposed on the WLED's luminous characteristics and the VLC channel response. The terminals were developed using ARM7-based embedded system, and experiments were carried out to derive their performances. A suitable illuminance of 200 lx (measured before the WLED) is preferred for obtaining a uniform bit error ratio (BER) over the distance of 0–2 m, and the measured BER is <10−4 with a communication data rate of 0.1–10 Mbps. High stability was also confirmed through measuring the BER results over 5 h at the two communication distances of 0.2 and 0.3 m and at 1 Mbps data transmission rate. Owing to the advantages of small size, low cost, and 10 Mbps data rate, this kind of terminals can be adopted in indoor short-distance wireless communication.

Comparative Study of Effects of Terminal Non‐Alkyl Aromatic and Alkyl Groups on Small‐Molecule Solar Cell Performance

Small‐molecule donors for solar cells are usually end‐capped with π‐systems or aliphatic chains extending the π‐conjugation of the molecules's backbone. Compared with alkyl terminals, π‐systems can form π−π arrangements, for example, with an aligning spherical fullerene π‐system. To study the effects of two kinds of terminals on the solar cell performance, the non‐alkyl, branched aromatic and electron‐donating diphenylamine (DPA) and the aliphatic n‐butyl (n‐Bu) unit are selected as end‐capping groups on a diketopyrrolo­pyrrole‐based linear backbone, affording two new solution‐processable small‐molecule donors. Photovoltaic data indicate that by changing the end‐function from n‐Bu to DPA, the photocurrent significantly increases from 8.35 to 15.64 mA cm−2 and the efficiency from 3.2 to 5.8%. Characterization of absorption, morphology, recombination, and carrier transportation clearly demonstrates that the higher photocurrent can be attributed to a higher density of the mobile carriers (i.e., free holes, in this case). The DPA end‐functions enhance the light‐harvesting capacity, improve the charge dissociation, and reduce the recombination loss, all of which lead to more carriers being collected by the electrode. This work demonstrates that the choice of end‐function along the molecular backbone is as important to improve the cell performance as the light‐harvesting backbone and the side‐chains.

The electro-acoustic transition process of pulsed corona discharge in conductive water

A pulsed corona discharge in conductive water is studied theoretically and experimentally via pre-discharge analysis, thermodynamic and dynamic processes of a plasma-containing bubble, an acoustic signature and energy partitioning. The total particle density and electron density inside the bubble, internal temperature and pressure, bubble radius and bubble wall Mach number are simulated by solving a set of equations including the ideal gas equation, Rayleigh equation and energy balance equation. The bubble radius is also measured by a high-speed charge-coupled device camera on a homemade experimental device. The acoustic waveforms and their power spectral density are calculated indirectly. By using several diagnostic tools, the electrical parameters of the load, light emission from the plasma and acoustic waveforms are recorded simultaneously. Simulation and experimental results of the bubble radius and acoustic signature agree reasonably well over the range of energy inputs from 5 to 30 J per pulse. Different kinds of terminations or intermediates of the energy transition process are analysed through simulation and experimental data. The electro-acoustic efficiency varies from 0.8% to 1.9%, while most of the discharge energy is consumed by circuit loss, Joule heating and thermal radiation, or is transformed into kinetic energy in the water.

Comparison of SiC Thyristors with Differently Etched JTEs

This paper presents results attained with SiC GTO thyristors terminated by a single step and a graded etched JTE. The comparison of both types of devices reveals no significant difference in the on-state and switching characteristics but a higher blocking capability of some thyristors with the latter kind of termination. The best devices showed a forward breakdown voltage of nearly 6 kV, which is a distinct progress as against previous results of thyristors with a graded etched JTE. Furthermore, such GTO thyristors have been characterized dynamically for the first time.

A Three-Way Remote Intelligent Terminal Based on Common Mobile

An intelligent terminal of telemetering, remote control and remote signaling which was capable of all the system operation regarding distant data transmission and monitoring on mobile, was assembled through the application of microcontroller and industrial communication module. Various physical quantities of devices could be measured and text-message transmitted by the designed multi-sensor. a microcomputer control center monitoring all kinds of terminals could be set up. The design can be further applied in Internet of Things.

Hayabusa—Its technology and science accomplishment summary and Hayabusa-2

Hayabusa performed five descents last November, among which two touching-down flights were included. Actually Hayabusa made three touching-downs and one long landing on the surface of Itokawa during those two flights. This paper summarizes how series of descents were planned and operated. The contents focus their attention on the correction maneuvers planning as well as what kind of terminals with what kind of software tools were actually built and used. The project team had distilled and accumulated their experiences through the rehearsal flights and accomplished this difficult mission. This paper presents the entire story about it.

Surface rumpling of cubic CaTiO 3 from density functional theory

In this paper, the structure of cubic CaTiO3 (001) surfaces with CaO and TiO2 terminations has been studied from density functional calculations. It has been found that the Ca atom has the largest relaxation for both kinds of terminations, and the rumpling of the CaO-terminated surface is much larger than that of TiO2-terminated surface. Also we have found that the metal atom relaxes much more prominently than the O atom does in each layer. The CaO-terminated surface is slightly more energetically favourable than the TiO2-terminated surface from the analysis of the calculated surface energy.

Effects of Bi and Pb on oxidation in humidity for low-temperature lead-free solder systems

The oxidation behavior of various Sn-Zn(-Bi) alloys during 60°C/90% and 85°C/85% relative humidity (RH) exposure were investigated by microstructure observation and x-ray diffraction analysis. The mechanical property of the joints of resistor chips (1608R) with two kinds of terminations, Sn and Sn-10Pb, soldered on a printed circuit board with Sn-Zn(-Bi) were evaluated by a shear test. The heat/humidity exposure of Sn-Zn alloys promotes segregation into the grain boundary accompanying oxidation of Zn resulting in the ZnO formation. This segregation induces serious degradation of alloys and Sn whisker growth. Heat/humidity exposure of 85°C/85%RH seriously decreases the shear strength of the surface mounted chip joints, especially Sn-Zn-Bi solder, due to the formation of ZnO at the interface between the solder and the reaction layer. The presence of Bi or Pb in Sn-Zn alloys enhances the diffusion, resulting in severe degradation at 85°C/85%RH exposure. In contrast, the exposure at 60°C/90%RH does not influence the joint strength for up to 1000 h. Under this condition, the oxidation of Zn only reaches a few microns in depth from the free surface.

A multiagent framework for pervasive computing: The mobeet framework

AbstractPervasive computing is becoming a more important issue for open distributed systems. It is, however, hard to design such distributed systems when the user uses many kinds of terminals and migrates with these. This paper has proposed a new framework for pervasive computing. The framework includes three kinds of agents: User Interface Agents, Programmable Agents, and Service Mediation Agents. We can easily design a flexible distributed system by collaborating these agents. We also evaluate the framework from the flexibility point of view. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(3): 49–64, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10375

A Multi Agent Framework for Pervasive Computing: Mobeet Framework

Pervasive computing is becoming a more important issue for open distributed systems. It is, however, hard to design such distributed systems when the user uses many kinds of terminals and migrates with these. This paper has proposed a new framework for pervasive computing. The framework includes three kinds of agents: User Interface Agents, Programmable Agents and Service Mediation Agents. We can easily design a flexible distributed system by collaborating these agents. We also evaluate the framework from flexibility point of view.

Dynamics of Pb deposits on theSi(100)2×1surface at room temperature

We have studied by scanning tunneling microscopy at room temperature the dynamics of Pb deposits on the $\mathrm{Si}(100)2\ifmmode\times\else\texttimes\fi{}1$ surface. The deposit consists of long one-dimensional rows of dimers (chains), where two kinds of terminations are observed. The long chains coexist with short ones, that consist of one or two protrusions. We have observed gains and losses of atoms at the end of these structures. From the analysis of these events, we have obtained information on the nature and the stability of the terminations, and on the nucleation process of the chains on the terraces.