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In this paper, a compact magnetic dipole composite right/left-handed transmission line (CRLH-TL) leaky-wave antenna (LWA) is proposed, which is periodically loaded with rectangular gaps and short stubs. And then, in light of the dielectric resonator with a high dielectric constant, low loss tangent and good radiation performance, we further add an alumina ceramic block (ACB) to stack on the gap in each CRLH-TL LWA’s unit cell for forming the magnetic dipole, thus, wide beam scanning range and compactness are achieved. To validate this design, a traditional uniform CRLH-TL LWA is investigated in detail. The results of S-parameters, electrical field distribution and radiation properties illuminate the effects of introducing the ACB, such as impendence matching improvement and high radiation efficiency. Furthermore, to verify the flexible control of the balanced condition and the attenuation constant by changing the microstrip gap width and the ACB thickness predicted in the circuit model analysis, a nonuniform CRLH-TL LWA with quasi-constant amplitude is fabricated. Experiment results demonstrate a higher antenna gain and the stability of wide beam scanning range under the condition of a compact design.

Thermo-active structures are underground facilities that enable the exchange of thermal energy between the ground and the overlying buildings, thus providing renewable means of space heating and cooling. Although this technology is becoming increasingly popular, the behaviour of geotechnical structures under additional thermal loading is still not fully understood. This paper focuses on the use of underground tunnels as thermo-active structures and explains their behaviour through a series of finite-element analyses based on an existing case study of isothermal tunnels in London Clay. The bespoke finite-element code adopted – the Imperial College Finite Element Program (ICFEP) – is capable of simulating the fully coupled thermo-hydro-mechanical behaviour of porous materials. The complex coupled interactions between the tunnel and the surrounding soil are explored by comparing results from selected types of coupled and uncoupled simulations. It is demonstrated that: (a) the thermally induced deformation of the tunnel and the ground are more critical design aspects than the thermally induced forces in the tunnel lining, and (b) the modelling approach in terms of the type of analysis, as well as the assumed permeability of the tunnel lining, has a significant effect on the computed tunnel response and, hence, must be chosen carefully.

This paper presents a conformal spiral antenna that is miniaturized and with dual-resonant for the wireless implantable capsule system. The spiral antenna conforms to a swallowable capsule with a radius of 3 mm and a length of 26 mm without occupying the internal space of the capsule. The compact antenna adopts two spiral arms to extend the effective current path for miniaturization. Biocompatible flexible polyimide was used as the dielectric substrate and capsule shell, achieving conformal properties of the antenna as well as compatibility with human tissue. The antenna has been simulated in different environmental models. The bandwidth of the antenna can reach 39.16 % (1.82 GHz-2.76 GHz) and 12.06 % (5.36 GHz-6.06 GHz) at 2.4 GHz and 5.8 GHz. The maximum gains of −35.2 dBi and −28.1 dBi can be achieved at 2.4 GHz and 5.8 GHz, respectively. In addition, the transmission characteristics of the antenna were experimentally verified in the minced pork and pig intestine. By analyzing the communication link, the communication distance between transceivers at 2.4 GHz and 5.8 GHz can meet 14 m and 5 m. These results show that the proposed antenna is suitable for wireless implantable capsule systems.

Today, with the continuous promotion and development of IoT and 5G technology, Cyberspace has become an important pillar of economic and social development, and also a foundational domain of national security. Cyberspace security is attracting more and more attention. Therefore, detecting malware and its variants is of great significance to Cyberspace. However, the increasing sophistication of malicious variants, such as encryption, polymorphism and obfuscation, makes it more difficult to identified malware effectively. In this article, a malware detection method of code texture visualization based on an improved Faster RCNN (Region-Convolutional Neural Networks) combining transfer learning is proposed. We utilize visualization technology to map malicious code into corresponding images with typical texture features, and realize the classification of malware. Firstly, in order to quickly acquire and locate the representative texture of malware, we adopt CNN to extract the global and deeper features of malicious code images. Then with RPN (Region Proposal Network) we generate the target image frame, which is used to locate the core texture of malware file (.text file), to realize the accurate positioning of malicious features. Secondly, we preprocess and train Faster RCNN model with ImageNet set, and then transfer the model to the malware classification model to accelerate the convergence of the first model and promote generation performance. Thirdly, we construct an improved objective function in which a novel multi-label of classification proportion is added to solve the problem that the texture change of “.text” section and other sections in malicious code image is not obvious after transfer learning. We collect code samples of six malware families from Kaggle platform, and compared the experimental results before and after transfer. The results show that the novel method can accelerate the convergence of loss function, and obtain higher accuracy (92.8%), lower FPR (6.8%) and better P-R (precision-recall) curve.

Emotion recognition has become increasingly prominent in the medical field and human-computer interaction. When people’s emotions change under external stimuli, various physiological signals of the human body will fluctuate. Electroencephalography (EEG) is closely related to brain activity, making it possible to judge the subject’s emotional changes through EEG signals. Meanwhile, machine learning algorithms, which are good at digging out data features from a statistical perspective and making judgments, have developed by leaps and bounds. Therefore, using machine learning to extract feature vectors related to emotional states from EEG signals and constructing a classifier to separate emotions into discrete states to realize emotion recognition has a broad development prospect. This paper introduces the acquisition, preprocessing, feature extraction, and classification of EEG signals in sequence following the progress of EEG-based machine learning algorithms for emotion recognition. And it may help beginners who will use EEG-based machine learning algorithms for emotion recognition to understand the development status of this field. The journals we selected are all retrieved from the Web of Science retrieval platform. And the publication dates of most of the selected articles are concentrated in 2016–2021.

Thermo-active structures exchange heat with the ground to provide thermal energy to buildings. Consequently, the ground is subjected to changes in temperature, inducing thermo-hydro-mechanical (THM) interactions within the soil. To provide insights into the origin and manifestations of the main mechanisms taking place in complex fully THM-coupled finite element (FE) analyses, simple, one-dimensional problems are firstly analysed in this paper and compared to analytical expressions developed for determining thermally-induced excess pore water pressures in undrained problems with different displacement restraints. Subsequently, various dimensionless parameters are established to evaluate the impact of varying ground properties on the observed THM interactions and their evolution with time. Finally, the findings from simple one-dimensional problems are verified in the context of THM modelling of thermo-active retaining walls, where the structural response of walls is shown to be highly transient and influenced by different phenomena prevailing over different periods involving thermal expansion of soils, volumetric deformations due to pore water generation and dissipation, and interactions with mechanical boundary conditions. The results also highlight the importance of performing fully coupled THM analyses and of a correct estimation of the hydraulic and thermal properties to guarantee a safe design of thermo-active structures.

Ground source energy systems (GSES) utilise low enthalpy geothermal energy and have been recognised as an efficient means of providing low carbon space heating and cooling. This study focuses on GSES where the exchange of heat between the ground and the building is achieved by circulating a fluid through heat exchanger pipes. Although numerical analysis is a powerful tool for exploring the performance of such systems, simulating the highly advective flows inside the heat exchanger pipes can be problematic. This paper presents an efficient approach for modelling these systems using the finite element method (FEM). The pipes are discretised with line elements and the conductive-advective heat flux along them is solved using the Petrov-Galerkin FEM instead of the conventional Galerkin FEM. Following extensive numerical studies, a modelling approach for simulating heat exchanger pipes, which employs line elements and a special material with enhanced thermal properties, is developed. The modelling approach is then adopted in three-dimensional simulations of two thermal response tests, with an excellent match between the computed and measured temperatures being obtained.

A new Petrov-Galerkin finite element method for two-dimensional (2D) highly advective flows in porous media, which removes numerical oscillations and retains its precision compared to the conventional Galerkin finite element method, is presented. A new continuous weighting function for quadratic elements is proposed. Moreover, a numerical scheme is developed to ensure the weighting factors are accurately determined for 2D non-uniform flows and 2D distorted elements. Finally, a series of numerical examples are performed to demonstrate the capability of the approach. Comparison against existing methods in the simulation of a benchmark problem further verifies the robustness of the proposed method.

Thermo-active foundations utilise heat energy stored in the ground to provide a reliable and effective means of space heating and cooling. Previous studies have shown that the effects of temperature changes on their response are highly dependent on their interaction with the surrounding ground. Consequently, it is necessary to consider this interaction and include both the thermal and mechanical behaviour of the ground in design. This paper addresses this issue by performing state-of-the-art finite-element analyses using the Imperial College Finite Element Program, which is capable of simulating the fully coupled thermo-hydro-mechanical behaviour of porous materials. First, the Lambeth College pile test is analysed to demonstrate the capability of the adopted modelling approach to capture the observed response under thermo-mechanical loading. Subsequently, a detailed study is carried out, demonstrating the impact of capturing the fully coupled thermo-hydro-mechanical response of the ground, the use of appropriate boundary conditions and the uncertainty surrounding thermal ground properties. It is demonstrated that the modelling approach has a large impact on the computed results, and therefore potentially on the design of thermo-active piles. Conversely, the effects of thermal conductivity and permeability of the soil are shown not to influence the pile behaviour significantly.

A wideband millimeter wave antenna operated at 37.5 GHz for 5G mobile communication technology has been proposed. The feed mode selects the substrate integrated waveguide (SIW), and grooving slots is used to increase the bandwidth of the antenna. Meanwhile, the whole dimension, 10 mm × 20.7 mm × 0.762 mm, is obtained. The derived radiation element was employed to improve the radiation effective. Finally, the proposed antenna was fabricated and tested. The result was consistent between simulated and experiment.

A implantable antenna is designed in this paper, which is implantable for the body area network application. To obtain the miniaturized size, the antenna is fed coplanar waveguide. Its thickness is less than 0.15 mm. Then the gap loading technique is used on the radiation patch to tune the center frequency and improved the bandwidth. A three-layer human body tissue model is built to imitate the simulation environment of the antenna accurately, and this model can improve the simulation results. Then we use the pork as experiment material where the antenna is put into. Experiment results show the bandwidth of the antenna is 4.5 - 8.6 GHz around the 5.8 GHz, which verified our designed antenna available.

Background The aim of the present study was to investigate the contribution of maturity-onset diabetes of the young (MODY) genes to the etiology of 14 Chinese MODY families and to assess phenotypic differences between patients with MODY but without a known genetic cause of diabetes (MODYX) and those with early onset type 2 diabetes (T2D). Methods The study included 14 MODY probands from unrelated families and 59 patients (age of onset ≤35 years) diagnosed as early onset T2D. A standard meal test and metabolic studies were performed to characterize the clinical features of all patients. All probands with MODY were analyzed for nucleotide variations in promoters, exons, and exon–intron boundaries of 13 known MODY genes by direct DNA sequencing. Results Mutations in 13 known MODY genes were not present in the 14 Chinese families and they were classified as MODYX. However, different polymorphisms were identified, with I27L (42.9%; 12/28) and S487N (46.4%; 13/28) of hepatocyte nuclear factor 4α (HNF1α/MODY3) being two most frequent polymorphisms. Two new polymorphisms, namely T412I and D504H, were detected in carboxyl ester lipase (CEL/MODY8). Compared with patients with early onset T2D, patients with MODYX were diagnosed with diabetes at a younger age (28.3 ± 6.5 vs 24.3 ± 6.5 years; P

A dual-band implantable microstrip antenna for wireless medical applications is designed, which can be used in the communications between medical equipment and human's body, even animal after it is implanted under the skin. Wireless medical service protocol includes wireless medical telemetry services and industrial, scientific, medical band, working frequencies are 1395–1400MHz and 902–928MHz. The meander-shaped microstrip-feed structure is in the design, which has the advantages of smaller size, easier adjustment, and better radiation performance. The simulation results from high frequency electromagnetic software show that the antenna can be worked at the frequencies above perfectly. The return loss is −19.5dB at 0.92GHz and −22.3dB at 1.40GHz, with the relatively bandwidth of 21% and 12.1%, respectively, which satisfied the needs of frequency of the system we mentioned.

© 2016 Elsevier Ltd.Ground source energy systems, such as open-loop systems, have been widely employed in recent years due to their economic and environmental benefits compared to conventional heating and cooling systems. Numerical modelling of such geothermal system requires solving a coupled thermo-hydraulic problem characterised by a convection-dominated heat transfer which can be challenging for the Galerkin finite element method (GFEM). This paper first presents the coupled thermo-hydraulic governing formulation as well as the coupled thermo-hydraulic boundary condition, which can be implemented into a finite element software. Subsequently, the stability condition of the adopted time marching scheme for coupled thermo-hydraulic analysis is established analytically. The behaviour of highly convective problems is then investigated via a series of analyses where convective heat transfer along a soil bar is simulated, with recommendations on the choice of an adequate discretisation with different boundary conditions being provided to avoid oscillatory solutions. Finally, the conclusions from the analytical and numerical studies are applied to the simulation of a boundary value problem involving an open-loop system, with the results showing good agreement with an approximate solution. The main objective of this paper is to demonstrate that the GFEM is capable of dealing with highly convective geotechnical problems.

To investigate the prevalence and clinical characteristics of ketosis-prone type 2 diabetes (KPD) in Chinese patients with young-onset diabetes.A total of 238 young diabetic patients were recruited from our inpatient department from January 1, 2012, to December 28, 2014. KPD was defined as diabetes without precipitating illness and with the presence of ketosis or diabetic ketoacidosis in the absence of autoantibodies at the time of diagnosis. We reviewed the clinical characteristics and disease progression of this group of patients.Eighteen patients fulfilled the criteria for KPD, and the prevalence of patients with KPD was 7.6%. The mean (SD) age of the KPD group at the time of diagnosis of diabetes was 27.6 (4.85) years, and these patients were predominantly male (male to female ratio, 8:1) and had a high proportion of obesity and new-onset diabetes and a strong family history of diabetes. β-Cell function in the KPD group was intermediate between type 1 and type 2 diabetes. Patients with KPD had the highest levels of glycated hemoglobin, triglycerides, total cholesterol, and free fatty acids and the lowest levels of high-density lipoprotein. After 3 to 12 months of follow-up, 17 of 18 patients with KPD (94.4%) were able to discontinue insulin therapy, and 11 patients (61.1%) were managed with diet or exercise alone.KPD patients accounted for 7.6% of the diabetic patients requiring admission to a large urban hospital in China, with an age of onset of diabetes of ≤35 years. These patients are more likely to be male, have abnormal lipid metabolism, and have more reversible β-cell dysfunction.