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BACKGROUND: The aim of this study was to explore the magnetic resonance enterography (MRE) imaging manifestations of a symptomatic Meckel’s diverticulum (MD) in pediatric patients in order to provide a reference for the diagnosis of the condition. METHODS: The medical records of 31 pediatric patients with MD from May 2014 to October 2020 were retrospectively analyzed. The inclusion criteria were patients with MD accompanied by unexplained gastrointestinal bleeding, anemia (except hematological diseases), chronic persistent abdominal pain, repeated intussusception, or intussusception in older pediatric patients during surgery. The clinical variables (age, sex, and hemoglobin) and imaging, surgical, and pathological findings were recorded. RESULTS: MD was definitively identified in 28 patients, with the following characteristics: a blind-ending fluid-filled and/or gas-filled structure (n=23), an elongated shape (n=1), a dumbbell shape (n=1), and a solid mass (n=3). The diverticula were located in the right lower quadrant (n=16), the right abdomen at the level of the umbilicus (n=3), the right upper quadrant (n=2), the left upper quadrant (n=2), and the midline lower abdomen (n=5). Supply arteries were visualized in nine cases. In all cases, mural enhancement was comparable to that of the adjacent small-bowel (SB). Extravasation of the intravascular contrast medium was seen in two cases. Peripheral structural abnormalities included mesenteric fat stranding (n=7), hemorrhage in the adjacent lumen (n=3), free intraperitoneal gas (n=1), abnormal fluid retention (n=2), intestinal obstruction (n=1), and lymph node enlargement (n=7). A normal appendix was identified in 18 cases. CONCLUSIONS: MRE is an appropriate method of diagnosing symptomatic MD in pediatric patients and is particularly useful in the assessment of complications.

Background: Bone marrow mesenchymal stem cells (BMSCs) transplantation offers an attractive strategy for treating multiply neurological diseases. Neuregulin1 (NRG1) plays fundamental roles in nervous system development and nerve repair. In this study, we aimed to investigate whether transplantation of NRG1-overexpressing BMSCs could alleviate spinal cord injury (SCI), and to explore the possible underling mechanisms. Methods: In vitro, NRG1-overexpressing BMSCs were constructed via plasmid transfection, and co-cultured with PC12 cells subjected to oxygen-glucose deprivation (OGD). Neurite outgrowth, cell viability and apoptosis of PC12 cells were evaluated. In vivo, BMSCs, empty-vector BMSCs and NRG1-overexpressing BMSCs were transplanted respectively into rats with SCI. Rat locomotor functions, neuronal chromatolysis, neurite outgrowth and cell apoptosis were assessed respectively. Results: The results showed that NRG1-overexpressing BMSCs in vitro significantly expedited neurite growth, elevated growth-associated protein 43 expression, enhanced cell viability and rescued ODG-induced apoptosis in PC12 cells. In vivo, transplantation of NRG1-overexpressing BMSCs notably accelerated rat motor functional recovery, attenuated neuronal chromatolysis, promoted neurite outgrowth and reduced cell apoptosis after SCI. Moreover, NRG1-overexpressing BMSCs were also able to regulate apoptosis-related proteins expression after SCI. Conclusions: These findings demonstrate that NRG1-overexpressing BMSCs can accelerate motor functional recovery by facilitating neurite outgrowth and reducing cell apoptosis after SCI, suggesting that NRG1-overexpressing BMSCs may be a promising candidate for the treatment of SCI.

Background: Spinal cord injury (SCI) is a severe neurological disorder for which there is currently no effective treatment. Electroacupuncture (EA) is a type of traditional acupuncture combined with modern electrotherapy, which has been widely used and verified to have neuroprotective effects. The aim of this study was to evaluate the effects of EA stimulation on the repair of SCI and to investigate the possible mechanisms. Methods: Sprague-Dawley rats were randomly divided into sham, sham+EA, SCI and SCI+EA four groups. Rat motor function was assessed by the Basso, Beattie and Bresnahan locomotor rating scale, inclined plane test and footprint analysis. Histological alterations of spinal cords were examined with hematoxylin-eosin and Nissl staining. Oxidative stress was evaluated by measuring reactive oxygen species (ROS), glutathione (GSH), total antioxidant capacity (T-AOC), 3-nitrotyrosine (3-NT), and 4-hydroxynonenal (4-HNE) levels. The changes in p66Shc expression and endoplasmic reticulum stress (ERS) were detected to explore the involved mechanisms.Results: EA stimulation significantly improved rat motor functional recovery, reduced spinal cord lesion cavity and neuronal chromatolysis after SCI. Concomitantly, EA stimulation alleviated oxidative stress, as indicated by suppression of ROS production, increase in GSH and T-AOC levels and reduction of 3-NT and 4-HNE expression. Further, EA stimulation markedly eliminated the aberrant increase of p66Shc due to SCI in rats. More notably, EA stimulation was also able to attenuate ERS via down-regulation of glucose-regulated protein 78, activating transcription factor 4, C/EBP homologous protein, X-box binding protein 1 and activating transcription factor 6 expression in rat spinal cord tissues after SCI. Conclusions: These findings suggest that EA is a potential strategy for treatment of SCI, and the mechanism might be, at least in part, associated with mitigation of p66Shc-associated oxidative stress and ERS in rats.

Heterogeneous cellular network is considered as an important network architecture to improve spectral efficiency and energy efficiency. Extensive research has revealed that spectral efficiency and energy efficiency could be two conflicting performance metrics under most scenarios. Toward the next generation 5G wireless systems, both spectral efficiency and energy efficiency become increasingly important. How to design a wireless system that jointly considers/optimizes these two performance metrics is critical yet challenging. This paper jointly analyzes the area spectral efficiency and area energy efficiency in a wireless heterogeneous network with inter-tier fractional frequency reuse. Proportional fairness resource allocation is used to balance the spectral efficiency and user fairness within each cell. A theoretical framework is formulated to analyze the area spectral efficiency and area energy efficiency in such a system. Fractional frequency reuse and proportional fairness resource allocation define the optimal power reduction factor and fractional bandwidth partition to maximize the joint area spectral efficiency and area energy efficiency. The system performance is evaluated by using the proposed scheme with different system parameter settings including base station densities, cell fractional bandwidth partition, power threshold, and base station power consumptions. The study shows that fractional frequency reuse with proper settings can significantly increase the area spectral efficiency and area energy efficiency in wireless heterogeneous networks.

The objectives of this study were to determine the protective effects of organic acids (OA) in broilers exposed to Salmonella Pullorum challenge at early stage and to explore the potential benefits of OA by metabolomics analysis. The treatment groups included non-challenged, S. Pullorum-challenged, challenged group supplemented with virginiamycin, challenged group supplemented with OA in drinking water, challenged group supplemented with OA in feed, and challenged group supplemented with OA in combination in drinking water and feed. Results showed that early Salmonella challenge induced an acute systemic infection of broilers in the starter phase, followed by the grower phase without triggering clinical signs. OA supplementation promoted growth during the grower phase, and while OA in water contributed more, the positive effects of OA in combination were comparable to those of virginiamycin supplementation in challenged birds. Furthermore, OA could modulate the systemic metabolic perturbation caused by challenge as it alleviated stress responses mediated by steroid hormone, potentially attenuated antioxidant or immune defense, and modified intestinal microbiota metabolism. These results show a metabolic mechanism that may partly explain the potential benefits of OA in Salmonella challenged birds, and may contribute to the use of OA to control or reduce S. Pullorum infection in farm animals.

Environmental concerns and depletion of traditional energy lead to the booming development of renewable distributed generation (RDG) in the past decade. However, due to intermittent nature of renewable energy sources, to what extent RDG could provide capacity to power systems becomes a critical issue to the utility company when implementing long-term system strategic (generation expansion) planning. On the other hand, in a smart-grid frame, the popularization of different varieties of demand-side resources enables the system to operate at more flexible modes ever before. The potential variability in load demand not only introduces additional dynamics and uncertainties to the system, but could also affect the reliability benefits of RDG. Therefore, in practice, to effectively estimate the reliability value of RDG in power systems, the potential interaction between generation- and demand-side must be properly captured. In this paper, a study to assess the capacity credit (CC) of RDG in a context of distributed generation system is performed with consideration of the impacts of demand response (DR). A compound reliability model for DR is presented, which considers the uncertainties involved in both instant response and follow-on load recovery processes. On this basis, an assessment framework for the CC of RDG based on sequential Monte Carlo simulation is developed by which the inter-temporal characteristics of DR resources can be fully captured. The numerical study is implemented based on the IEEE-38 bus test case. The calculation results demonstrate that the CC of RDG would depend on a variety of factors, including penetration level, responsiveness of load demand and the correlations between RDG and DR availability. Also, it is shown that accounting for the underlying effect of DR is of absolute importance, otherwise the CC of RDG might be estimated erroneously in real practices.

As an integral feature of a future smart grid, demand response (DR) provides utility companies an emerging alternative to boost the reliability performance (e.g., supply adequacy) of power systems. Unlike for physical devices, the availability of DR is not only dependent on the operations of electric appliances on the demand side but can be affected by customers’ behaviors. Thus, how or to what extent DR actions can affect power system reliability becomes an important issue for utilities. In this paper, a new approach for assessing the contribution of incentive-based DR to the supply adequacy of smart distribution systems (SDS) is presented. Compared with existing methods, our method explicitly captures the varying availability of customer DR capabilities. We introduce a behavior-reinforcement procedure to model the correlation of users’ participation willingness with their historical DR profitability. Then, a strategic DR dispatch strategy can be developed to optimize users’ DR availability bids in the market. In addition, the interdependency between a communication system and DR operation has also been considered. A hybrid algorithm based on sequential Monte-Carlo simulation and an optimal load dispatch method is employed to evaluate the system reliability in this context. The proposed approach is illustrated using both a small-scale test case and a real regional distribution grid in China. The results demonstrate the effectiveness of the presented method.

World egg production and consumption have been increasing for the past decades. Traditional strategies in poultry nutrition have made vital contributions to this great growth in quantity. However, current global issues should be considered in modern egg production such as growing populations and food security, food safety and quality, limited resources and environmental problems. The development of knowledge of poultry nutrition and modern biotechnology provides novel nutritional approaches to closely fit the requirement of pullets and laying hens, which will consequently decrease the nutrition excretion and maintain the lower cost of feed. Nutrition has also been widely accepted as a strategy to influence health and diseases of laying hens. The maintenance of good health is an important prerequisite for improving productivity and egg quality. In addition, there are many measures and strategies for minimizing the incidence of egg defects and providing a choice of lifestyle to enhance human health. This paper reviews current research progress on developing innovative technologies and strategies to maximize animal health and performance, improve the quality of egg products and minimize pollution caused by poultry production.

A 6-week experiment was conducted to evaluate the effects of dietary oregano powder (OP) supplementation on the growth performance, antioxidant status and meat quality of broiler chicks. A total of 180 one day-old Arbour Acres broilers were randomly divided into 3 treatments with 6 replicates and 10 chicks per replicate. The chicks were fed with basal diet without (CTR), or with 20 mg/kg of virginiamycin (ATB), or with 150 mg/kg of OP. At 21 and 42 days of age, two birds from each cage were selected for sampling. Compared to the CTR group, the OP supplementation increased average daily gain and average daily feed intake during the grower period (p = .047 and .03, respectively) and the whole period (p = .04 and .02, respectively). The supplementation of ATB and OP did not affect the immune organ index of chicks. In addition, dietary OP reduced malondialdehyde content and increased total antioxidant activity (T-AOC) in the serum of chicks at 21 (p

The beta-phase of Zn4Sb3 has been regarded as a very promising thermoelectric material since middle nineties, owing to its unique merit: intermediate temperature region (200-400 °C), made of cheap, non-toxic and abundant elements and high thermoelectric property. However, the thermal stability of Zn4Sb3 seems to be an inherent obstacle for the practical application during the working temperatures. Herein, magnesium doped Zn-Sb semiconductor (Mg0.04Zn3.96Sb3) was investigated thoroughly in-situ during thermal annealing up to 600 K, whilst both microstructure and electronic structures were recorded via the combination of synchrotron-based two dimensional X-ray diffraction techniques and the X-ray photoemission spectroscopy. While the time-resolved grazing incidence XRD reveals the preserved crystal structures during thermal annealing to 600 K, XPS measurement demonstrate the robustness of electronic structures. On basis of these findings, it was concluded in the end that the doping of magnesium significantly improves the thermal stability of zinc-antimonite compounds and introduces minor influence on the electronic structure of Zn-Sb alloy. Our study may propose an effective approach towards the wild application of Zn4Sb3 related thermoelectric materials.

Device-to-device (D2D) communications are usually considered to be two user equipment units (UEs) communicating directly without going through the central base station (BS). In fact, they can be further broadened to multihop D2D communications in which a UE may help other UEs communicate with each other or assist other UEs to communicate with the BS. In this paper, the authors investigate a scenario of multihop D2D communications where one UE may help other two UEs to exchange information with a two-time-slot physical-layer network coding scheme. The authors analyze the average energy efficiency and spectral efficiency of multihop D2D communications under Rayleigh fading channels and get close analytical approximations based on Taylor series expansion. Comparisons with direct D2D communications and traditional cellular communications through BS are provided. The optimal UE transmission powers of these three different modes to maximize the energy efficiency are also derived.

Key Clinical Message We described a combined periodontal–endodontic lesion, which was caused by a palatogingival groove and an additional root. An interdisciplinary approach involving endodontic therapy, mineral trioxide aggregate (MTA) filling, root resection, guided tissue regeneration, and papillary reconstruction was used for the case. The tooth presents morphologically and functionally normal except tooth discoloration caused by MTA.

This study was conducted to evaluate the effects of various protein sources (soybean meal, SBM; cottonseed protein, CSP; double-zero rapeseed meal, DRM) on the internal quality of refrigerated eggs. A total of 360 laying hens (32 wk of age) were randomly allotted to six treatment groups (five replicates per treatment) and fed diets containing SBM, CSP, or DRM individually or in combination with equal crude protein content (SBM-CSP, SBM-DRM, and CSP-DRM) as the protein ingredient(s). A 6×3 factorial arrangement was employed with dietary types and storage time (0 d, 2 wk, and 4 wk) as the main effects. After 12 wk of diet feeding, a total of 270 eggs were collected for egg quality determination. The egg Haugh unit (HU) in the CSP, SBM-DRM, and DRM groups were significantly lower than those in the SBM and SBM-CSP groups. The hardness and springiness of the cooked yolk in the CSP group were significantly higher than those in the other treatment groups. A lower HU, lower yolk index and higher albumen pH were observed in the DRM group compared to the SBM and SBM-CSP groups when the eggs were stored to 4 wk, and the HU was improved in the CSP-DRM group compared to the DRM group (p

This paper assesses 30 provinces’ data in China by using a network DEA model with undesirable output. The results denote that the proposed model could evaluate the internal energy consumption well. And the main cause of the energy inefficiency is environmental inefficiency. Therefore, China’s provinces should tighten restriction on CO2 emissions and reduce their dependence on fossil fuels by using more green energy.

Following the proposal of the “Belt and Road” strategy, Xinjiang has gradually become a critical wind power base and energy transmission channel in China. At present, however, much of Xinjiang's potential wind power is being curtailed. Owing to Xinjiang's strategic position, this issue may negatively impact wind power development in Xinjiang and China's overall energy strategy, and it is thus necessary to identify the causes of and solutions to wind power curtailment in Xinjiang. This study analyzes the problem of wind power development in Xinjiang, and proposes both technical and market policy measures. The research results show that establishing a regional power spot market and improving power system flexibility are the fundamental ways to solve the problem of wind power curtailment in Xinjiang.

The ever growing demand of Internet of Things (IoT) devices for wireless access imposes great challenges in the current cellular systems and call for novel approaches for wireless network design. This paper considers a hierarchical cloud-fog communication network. By using the real-life user data, following the long-term data features and combing with online bandit saddle-point (BanSap) method in short-term, we develop a joint energy and time consumption optimization method for fog and cloud computing for IoT network. The number of active servers in the access layer is optimized based on the workload prediction model. Simulation results show that our proposed scheme can achieve a better performance in delay and energy consumption.

In recent years, the container liner industry is gradually changing from liner conference mode to liner alliance mode. The joint dispatch and mutual renting of shipping is a common strategy adopted by liner alliances. This paper bases on the multi-dimension of container type, size, deadweight tonnage and capacity, combined with long-term contractual customer booking requirements and the randomness of supply demand. It takes the total marginal transportation income and its rental income maximization as the goal to establish a stochastic allocation model. This model is transformed into an integer linear programming model by using the robust optimization method, which can be solved by Lingo software package. Finally, the result of a numerical example shows that adopting the strategy of joint dispatch and mutual renting can bring the most benefit to the enterprise.

The abundant spectrum in millimeter wave (mmWave) bands provides an opportunity for fifth generation (5G) cellular communication systems to enhance their mobile broadband services. mmWave communication is therefore considered as one of the key features of 5G cellular radio access network (RAN). However, the deployment of mmWave cellular RAN faces challenges due to mmWave radio propagation characteristics such as pathloss, blockage and penetration loss. In this paper, we investigate the performance of mmWave cellular RAN using system level simulations based on the 3GPP evaluation methodology and applying techniques such as cell densification, wireless backhaul, and sub-6 GHz and mmWave dual access.

In this work, based on current 5G New Radio (NR) SYNC/RACH slot structures, we focus on initial access (IA) techniques when the base stations (BSs) and the user equipments (UEs) are equipped with uniform planar array (UPA) antennas and without context information from macro BSs. With different omni/beam antennas and exhaustive/iterative search, we present five possible IA schemes: (i) BS omni/UE omni as a reference; (ii) Exhaustive Search 1; (iii) Exhaustive Search 2; (iv) Iterative Search 1; (iv) Iterative Search 2. Through simulations and comparisons, we demonstrate the comprehensive consideration of IA scheme selection with respect to coverage/SNRs, search delays and BS/UE antenna array settings.

Heterogeneous networks improve the spectrum efficiency and coverage of wireless communication networks by deploying low-power nodes on top of the conventional network nodes. In this paper, we consider a heterogeneous cellular network with multiple low-power relay nodes (RN) deployed in each cell using in-band wireless backhaul link between the RN and the base station (BS). The RNs work cooperatively with the BSs on the downlink communication towards the user equipments. Due to the disparity between the transmit powers of the BSs and the RNs, mobile association schemes developed for the conventional homogeneous networks may lead to a highly unbalanced traffic load distribution with most of the traffic being concentrated on the BSs. In this paper, we propose a new mobile association framework for the heterogeneous wireless networks with node cooperation. The proposed framework aims to maximize the network capacity and balance the traffic load among the network nodes. A pseudo-optimal solution is obtained for the proposed mobile association framework using a centralized gradient-descent algorithm. To enable online implementation, we further introduce a distributed algorithm using a pricing mechanism. Numerical results show that a prominent improvement in network capacity can be achieved by the proposed load balancing-based mobile association scheme compared with the conventional counterpart. Moreover, compared with the pseudo-optimal solution, the proposed pricing-based distributed algorithm only suffers a small loss in network capacity and thus can be considered as an efficient real-time implementation alternative.

Current cellular spectrum at below 3 GHz bands is experiencing severe shortage and cannot keep up with the dramatic proliferation of mobile traffic in the near future, requiring the search for innovative solutions to enable the 5G era. mmWave communications, with a possible gigabit-per-second data rate, have attracted great attention as a candidate for 5G broadband cellular communication networks. However, a complete characterization of mmWave links for 5G wireless networks still remains elusive and there are many challenges and research areas that need to be addressed. In this work we discuss several key elements to enable mmWave communications in 5G: · Channel characteristics regarding mmWave signal attenuation due to free space propagation, atmospheric gaseous and rain are explained. · The hybrid (digital plus analog) beamforming architecture in mmWave system is discussed. · The blockage effect in mmWave communications due to penetration loss and possible approaches are presented. · The application of mmWave transmission with narrow beams in non-orthogonal device-todevice communication is proposed. · mmWave transmission in the booster cell of heterogeneous anchor-booster networks. · mmWave transmission for small cell backhaul is further discussed.

Analog/digital/hybrid beamformer/receiver designs for mmWave communication have attracted great research attentions including directional of arrival (DOA) estimation. Traditional investigation of smart antennas for wireless communications has primarily focused on uniform linear array (ULA) antennas and there are little attention and literature on other smart antennas array topologies. Those DOA estimation algorithms designed for ULA (with received signal as a vector) can not immediately be applied for uniform planar array (UPA) structure (with received signal as a matrix). In this work, start with UPA DOA estimation system model, we process the received matrix through a simple vectorization process to construct a received vector. With theoretical proof of the vectorization process equivalence, conventional DOA estimation based on ULA can easily be applied to UPA structure. We apply several DOA estimation algorithms to UPA for one DOA arriving signal or multiple DOA arriving signals, with both perfect known autocorrelation matrix and estimated autocorrelation matrix through sample averaging, and demonstrate the effectiveness of our proposed DOA estimation process for UPA.

In millimeter wave (mmWave) communications with possible gigabit-per-second data rate, the severe path loss can effectively be alleviated by adaptive beamforming using antenna arrays. However, this complicates the initial access (IA), by which a mobile user equipment (UE) establishes a physical link connection with a mmWave base station (BS). The total duration of IA directional search can be very long since multiple preambles should be repeatedly transmitted for all transmit and receive beam pairs. In this work, we focus on IA techniques based on analog beamforming with uniform planar array antennas without context information from microwave BSs. We revisit current techniques of exhaustive search and iterative search based on BS training, and propose a novel hybrid training method, where in the first stage BS performs wide beam search, and in the second stage, the UE will perform reverse training according to the best wide beam decided in the first stage. For the three IA techniques, we derive the total consumed time slots and the received SNR expressions in each stage. Through simulations and comparisons, we demonstrate that the proposed hybrid training method shortens the searching delay and gives the same access error probability as iterative search.

We consider a multi-source two-way relay network, in which one source communicates with N other sources n = 1,2,',N with the help of a single amplify-and-forward relay. We propose two opportunistic source scheduling schemes in such a network. According to the proposed schemes, in each transmission interval, only a single out of the N sources is selected, and this selected node acts as either transmitter or receiver depending on the channel conditions. For both schemes, tight closed-form lower bounds of outage probability and bit error rate BER are derived. Asymptotic outage probability and BER that are valid for high signal-to-noise ratio regime are also analyzed, which can provide important insights on the impact of system parameters. The analytical results show that the full diversity order N + 1 can be achieved by both proposed schemes. Simulation results are also presented to corroborate the analysis. Copyright © 2014 John Wiley & Sons, Ltd.

Device-to-device communication underlaying a cellular network is a promising technology in future wireless networks to improve network capacity and user experience. While D2D communication has great potential to improve wireless system spectral and energy efficiency due to the proximity of communication parties and higher spectrum reuse gain, tremendous work is still ongoing to turn the promising technology into a reality. This article discusses D2D technical challenges as well as standards progress and important research aspects that enable D2D communications underlaying cellular networks. The key research areas addressed include interference management, multihop D2D communications, and D2D communications in heterogeneous networks. When enabling D2D communications underlaying cellular networks, D2D communications can use either cellular downlink or cellular uplink resources. The two resource sharing modes will create different interference scenarios. The performance evaluation on D2D communications underlaying cellular networks under these two different scenarios is provided.

Because of the inevitable trend of green networking, energy efficiency EE is quickly becoming one of the key performance metrics to evaluate wireless communication systems, together with spectrum efficiency SE and quality of service QoS that have been traditionally used. This paper studies the fundamental tradeoff between EE and SE in the presence of statistical QoS requirements in wireless transmission systems. Earlier studies have shown that the performance with QoS requirements in the wireless transmission can be measured through effective capacity, which can capture the physical layer fading channel characteristics in the link layer QoS requirements, such as delay and data rate. Under this context, SE is defined as effective capacity per unit frequency bandwidth, and EE is defined as energy consumed per effective capacity bit. Both circuit power and transmission power are considered in the energy model, based on which we derive the quasi-convex generalized EE formulation. To exploit the tradeoff between EE and SE with QoS considerations, we propose a generic close-form approximation for EE-SE formulation by employing a curve fitting approach. The impacts of QoS and circuit power consumption on EE-SE tradeoff are respectively analyzed. QoS requirement and circuit power consumption affect the EE-SE tradeoff differently. In the low-SNR regime, circuit power shows more impact on the EE-SE tradeoff, whereas QoS impacts EE-SE tradeoff more in the high-SNR regime. Copyright © 2014 John Wiley & Sons, Ltd.

It has been projected that, in the next decade, a mobile traffic increase on the order of 1,000 times is expected compared to what we experience today. To meet that dramatic traffic growth, next-generation mobile networks are also expected to achieve a 1,000-fold capacity increase compared to the current generation of wireless network deployments. In this article, we discuss how such capacity growth could be achieved in a ten-year time frame. We discuss the techniques that we expect to have the highest opportunity for increasing the system capacity and estimate their gains based on analysis and simulation. We observe that the main driver of capacity growth is expected to come from network architecture advancements, with heterogeneous networks and convergence of information and communication technology being two of the key techniques. We also estimate that the air-interface evolution would focus not only on improving the link and system spectrum efficiency but also on facilitating the required network efficiency improvements. This article provides insights into the communication technology evolution and can be used as a guideline for technology development toward the fifth generation (5G).

In this work, we consider the problem of distributed link scheduling for D2D communications without a centralized controller. Our design goal is to maximize a chosen global objective function. For example, maximizing the long-term proportional fair throughput amongst distributed links can be such a goal. In principle, each link evaluates whether its rate increase by raising its transmit power is sufficient enough to compensate others' rate decrease due to increased interference power towards the objective function maximization. To this end, an iterative distributed power control algorithm, called PowerD2D, and supporting frame structure and signaling method are proposed. As a result of link scheduling via PowerD2D, some links are completely turned off by setting their transmit power to zero and some scheduled links are assigned non-negative transmit power, which are all set for optimality. In addition to its superior performance, PowerD2D algorithm is also flexible enough to enforce any level of fairness amongst links in a distributed manner.

Taking a pumping station project with large scale centrifugal pumps as working example, an extreme transient flow in the pumping system caused by tripping pump due to electric supply failure was analyzed, and hydraulic disturbance or impulsion to the rest working running pumps were investigated by using the software of the Deltares WANDA 3.73. The results show that the rest running pumps in the system due to a sudden tripping pump disturbance are heavy disturbed when the tripping pump is suddenly failed from the pumping system. The flow rate and input power for the working pumps are greatly jumped shortly. The strongly transient impulsion to the pumping system is quite significant.

With macro and micro base stations (BSs) of different transmission and processing capabilities jointly deployed, heterogeneous networks effectively extend the coverage and capacity of wireless networks and have been adopted as one of the key technologies in Fourth-Generation-Long-Term Evolution (4G-LTE). To fully exploit the benefits of heterogeneous networks, proper mobile association, interference management, and radio resource management schemes need to be developed. In this paper, we investigate radio resource allocation for heterogeneous networks with cooperative relays, where the relay nodes (RNs) with in-band backhaul act as micro BSs and are able to serve user equipment (UE) either independently or cooperatively with the BSs. In such a network, radio resource-allocation schemes need to decide for each resource block: 1) whether a UE is served by a BS or an RN, and 2) whether a UE should be cooperatively served or not. In making these decisions, radio resource consumption on RN's in-band backhaul links and fairness among the UEs should be taken into consideration, which further complicates the resource-allocation problem. In this paper, we propose a radio resource-allocation framework and derive a resource-allocation strategy that is asymptotically optimal on the proportional fairness metric. The derived resource-allocation scheme gives insights on the optimal radio resource allocation for the heterogeneous networks with cooperative RNs using in-band backhauls.

Intense global competition and declining profit have caused most thin film transistor liquid crystal display manufacturers to increase their competitiveness by improving productivity and reducing cycle times. An advanced planning and scheduling (APS) system was developed with Microsoft Visual Basic for Application to automatically generate production schedules for a color filter fab with multiple lines. This system can assign orders to production lines, plan order release time, and balance the equipment loading. Both forward scheduling and backward scheduling were used in APS. Experimental results indicated that APS can significantly reduce manual scheduling time while maintaining the quality of scheduling results. Compared to manual operations, it can save more than 87 % of scheduling time and the quickness is especially important when rescheduling is needed due to production uncertainties such as equipment breakdown or material shortage. Production controllers can use this APS to generate initial schedule and make adjustment based on experience.

Non-orthogonal multiple access (NOMA) is an emerging technology that can improve system spectral efficiency. In this paper, we propose a downlink multiple-input-multiple- output (MIMO) wireless system that incorporates NOMA. To make the system model more realistic, error propagation in successive interference cancellation (SIC) is considered during the decoding process. We formulate an optimization problem aiming at maximizing system throughput. The imposed error propagation increases the complexity to find a closed-form solution, so a heuristic way is proposed to solve the precoding matrix by an iterative algorithm. Case studies are performed to evaluate the impact of power allocation with residual interference afterwards. Simulation results show the superiority of the proposed precoding design and give an insight on power allocation.

Device-to-device (D2D) communication has attracted great attention and becomes a promising technology for future wireless networks. Besides two UEs communicating directly without going through the base station, D2D communication can be further broadened to multi-hop D2D communication, for example, a UE may serve as a relay for some D2D pair. In this work, we perform system-level simulation studies on multihop D2D communications overlay LTE networks with intra-cell and inter-cell interference from other D2D transmissions. We investigate dynamic scheduling for multi-hop D2D according to instantaneous channel and interference situation based on proportional fair metrics. Dynamic scheduling is a compromise between average and edge spectral efficiency, since using relays can increase edge performance but may decrease the average spectral efficiency as they consume more resources than direct D2D. In simulation studies, we can see that multi-hop D2D with dynamic scheduling outperforms direct D2D and multi-hop D2D with fixed scheduling for large D2D distance, and also increases edge spectral efficiency dramatically for small D2D distance with the expense of a little average spectral efficiency decrease.

Device-to-device (D2D) communication has attracted great attention and becomes a promising technology for future wireless networks. In this work, we perform system-level simulation studies on multi-hop D2D communications overlay LTE networks, i.e., D2D multi-hop links are given dedicated cellular resources in LTE networks. There still exist intra-cell interference and inter-cell interference from other D2D transmissions. We investigate several key technologies for multi-hop D2D communications in LTE system-level simulations, including user dropping, centralized scheduling for multi-hop D2D, hybrid automatic repeat request (HARQ), power control scheme, etc. After the system-level simulation platform setup for multi-hop D2D communications overlay LTE networks, we carry out simulation studies with respect to different D2D pair distances and different number of D2D pairs within a cell. This multi-hop D2D communications system-level simulation platform for LTE networks build a solid and practical ground for further multi-hop D2D communications technology investigation.

In this work, we consider the device-to-device (D2D) communications underlaying cellular networks to support local communication needs. In particular, we focus our attention on the design of an optimal resource allocation and mode selection algorithm for both cellular and D2D users. In the design, communication mode selection for D2D users is also taken into account so that a D2D source-destination pair has an option to either directly communicate or indirectly communicate through the base station (BS). On the other hand, it is necessary and important to provide a certain level of Quality of Service (QoS) to users. The users can be further differentiated by assigning different weighting factors and QoS requirements. To this end, we formulate a problem of maximizing the weighed sum rate of all the users constrained by their power and QoS requirements. The tool that we use to handle this problem is the primal-dual technique which transforms the original problem into the equivalent problem showing lower computational complexity. The simulation results verify that our proposed scheme outperforms the previous heuristic scheme by jointly optimizing the power and resource allocation along with the communication mode selection for the D2D communication pairs.

The renewable distributed generation (RDG) has gained booming development in the past decade, thus its capability to displace conventional generation has become an urgent issue to be studied for future power system planning. In this paper, the capacity credit (CC) of RDG is investigated given an active distribution system (ADS) context, wherein the impact of demand response (DR) is highlighted. To achieve this, the CC index is first specified to cater for different operating modes of ADS. On this basis, a generalized possibilistic-probabilistic model is proposed for DR characterization. The CC is calculated using the sequential Monte-Carlo simulation (SMCS) method, embedded with an adaptation strategy developed to improve the computation efficiency. Numerical results on a real multi-voltage distribution network show that the CC of RDG varies with the energy mix in ADS and the presence of DR could substantially improve the CC of RDG.

Because of high frequency and rotation speed, the analysis and design methods of high speed machine are different from conventional ones, such as rotor stress calculation, rotor dynamics analysis and electromagnetic design. In view of an outer rotor permanent magnet claw pole machine proposed, the claw pole and wingding were designed and analyzed by equivalent magnetic circuit and finite element method (FEM); the rotor stress distribution were calculated to check its strength; and the rotor bending mode and critical speed were simulated to analyze dynamics properties. Finally, a prototype of 1.5kW was developed, then the test research of prototype was carried out, the feasibility and accuracy of theoretical analysis have been verified by experimentation.

Images from the superresolution refers to a series of low resolution observation image reconstruction of high resolution images. Compressed and shaping of diffractive spot with the throne of circular mask is studied in this article, in order to improve the resolution of the image. Theory and simulation results of superresolution is given based on the diffraction spot compression and shaping in this paper，Which is very important for the study in laser communications and other field.

Intense global competition and declining profit have caused most Thin Film Transistor - Liquid Crystal Display (TFT-LCD) manufacturers to increase their competitiveness by improving productivity and reducing cycle times. This research developed Automated Scheduling and Dispatching (ASD) system to automatically generate production schedules for multiple color filter fabrication plants in TFT-LCD industry. On the basis of backward scheduling and forward scheduling, ASD was developed to estimate future equipment loading and calculate order due dates according to capacity limits by taking into account the due date and size of orders, as well as the capacity, loading, and yield of fabrication plants. ASD system can assign orders to production lines, plan order release time, and balance equipment loading. Microsoft Visual Basic for Application (VBA) was used to develop ASD system in this research. Preliminary results in a case study demonstrated that ASD can efficiently generate scheduling results. ASD has been partially implemented in the studied color filter fabrication plants. Compared to manual operations for scheduling and dispatching, more than two-third time was saved by using ASD. Further improvement is under study and development.

As we know , the materials will swell and contract when it is heated or cooled . A kind of method for mastery the real contractive rate of alloy was bring forward through researching the contractive rate of alloy. Using the method a inspecting testing mould of alloy was designed , and the real contractive rate was mastered by the mould . And this provides the reliable contract date for the design of mould cavity dimension , and reduces the work of mould repair , and also save a lot of money and labor.

Disruptive innovations in mobile broadband system design are required to help network providers meet the exponential growth in mobile traffic demand with relatively flat revenues per bit. Heterogeneous network architecture is one of the most promising low-cost approaches to provide significant areal capacity gain and indoor coverage improvement. In this introductory article, we provide a brief overview of heterogeneous network architectures comprising hierarchical multitier multiple radio access technologies (RAT) deployments based on newer infrastructure elements. We begin with presenting possible deployment scenarios of heterogeneous networks to better illustrate the concepts of multitier and multi-RAT. We then focus on multitier deployments with single RAT and investigate the challenges associated with enabling single frequency reuse across tiers. Based on the spectrum usage, heterogeneous networks can be categorized into single carrier usage, where all devices within the network share the same spectrum, and distinct carrier usage, where different types of devices are allocated separate spectra. For single carrier usage, we show that interference management schemes are critical for reducing the resulting cross-tier interference, and present several techniques that provide significant capacity and coverage improvements. The article also describes industry trends, standardization efforts, and future research directions in this rich area of investigation.

Is M2M hype or the future of our information society? What does it take to turn the M2M vision into reality? In this article we discuss the business motivations and technology challenges for machine-to-machine communications. We highlight key M2M application requirements and major technology gaps. We analyze the future directions of air interface technology improvements and network architectures evolution to enable the mass deployment of M2M services. In particular, we consider the salient features of M2M traffic that may not be supported efficiently by present standards, and provide an overview of potential enhancements. Finally, we discuss standards development for M2M.

A kind of U type 90°or V type 90°bending springback testing die was set up to discuss the bending springback . The springback of material can be masteried through setting up of bending springback adjusting test die without prior calculation . In order to adjust the bending angle , the T type slide seat and bending press plate were used and the adjusting of bending radii was implemented by replacing the adjusting axis of bending radii. At first, if the springback value of the sheet metal made sure for the die design , then the die was designed , the large of works for repaired and tested die were reduced and it will be the `most convenient for the die designer.

Spontaneous neoplasm metastasis, a fatalist pathological feature of cancer, is a long-evolving, multi-steps process that can now only be treated or controlled by drugs or immuno-modulators. As we have previously hypothesized, each drug or immuno-modulator might act differently within various stages of a metastasis. Therefore any researches helping to determine these differences will be beneficial for updating therapeutics for metastasis. In this work, we have testified this hypothesis by using a series of well-known anti-metastatic agents – Bisdioxopiperazine compounds.

Object The development and preclinical assessment of new endovascular devices necessitate readily available and reproducible animal models. The purpose of this study was to develop an in vivo carotid siphon model for testing the properties of covered stents specially designed for the intracranial vasculature. Methods Six carotid siphon–shaped devices were created. Six dogs underwent surgery to expose and isolate both common carotid arteries (CCAs). The right CCA origin was ligated and incised distal to the ligation point after temporary constriction of the distal right CCA. The distal left CCA was ligated and incised proximal to the ligation point after the left CCA origin was temporarily clamped. The proximal isolated left CCA was passed through the shaped device and then anastomosed end-to-end to the distal isolated right CCA. Finally, the shaped device was fixed and embedded in the neck. Intraarterial digital subtraction angiography was performed at 7 days, 2 weeks, and 1 month postprocedure. All models underwent endovascular interventional simulation. The carotid siphon models were evaluated. Results The animals tolerated the surgical procedure well. The mean time for surgical construction of the model was 90 minutes. The morphology and endovascular manipulation of the siphon models were similar to those in humans. Stenosis of anastomotic stoma occurred in 2 models, and mural thrombosis of anastomotic stoma occurred in 1 model; however, all models were patent at postprocedural follow-up angiography. Conclusions Surgical construction of an in vivo carotid siphon model in dogs with carotid siphon–shaped devices is feasible and potentially useful for testing neurovascular devices.

In order to exploit millimeter wave (mmWave) bands for 5G communications, challenges mainly due to blockage and strong dependency on beamforming operation need to be overcome. In this work, we address some of the fundamental issues related to the use of mmWave bands for 5G communications, from propagation channel characteristics and modeling to the implications on system and network architecture design. A statistical mmWave channel model considering cluster-level spatial/temporal correlation is proposed. System-level simulation results based on the proposed model demonstrate the channel characteristics and system performance. Following that, key techniques in enabling mmWave system operation are discussed. Although we believe that mmWave bands can be utilized in 5G networks, significant efforts and time are needed in order to complete the air interface, device and network design which is shown to be quite different from the existing cellular design.

We consider the problem of resource sharing in Device-to-Device (D2D) communication underlaying cellular networks. The problem is formulated as a non-cooperative game in which mobile users, either legacy cellular users or D2D users, decide their respective transmission power over available resource blocks (RBs) with the goal of maximizing their own utility function. The key factor that distinguishes our work from the existing literature is the design of the utility function; the utility function of each user is defined as the achievable rate normalized by the power consumption, which is in [bits/sec/Joule]. Such a utility function well reflects the users' satisfaction in reality when users are mobile and subject to the availability of energy due to the finite battery capacity and limited recharging facility. The scenario where the cellular and the D2D connections share the same resources is considered, in which the interference management between cellular and D2D communications is of great importance to guarantee the performance of high-priority cellular users. The most energy efficient strategy turns out that a DUE allocates the least amount of power on the channel with the best channel gain-to-interference-plus-noise-ratio (CINR) yet still achieves the highest data rate on that channel while a CUE allocates the optimal power on its assigned channel to reach the maximum energy efficiency.

We consider the adoption of listen-before-talk (LBT) for Long Term Evolution (LTE) in unlicensed spectrum, which is currently under discussion in the 3rd Generation Partnership Project (3GPP). The first and foremost task to be done to allow LTE to use unlicensed spectrum is to study the coexistence with incumbent system, such as the Wireless Local Area Network (WLAN). In our study, we observe that a proper coexistence mechanism is imperative especially when both LTE Evolved Node Bs (eNBs) and WLANs are located outdoor. The outdoor deployment scenario is considered by the next generation WLAN, the IEEE 802.11ax, with high importance. The implementation of LBT in LTE plays an effective role in this scenario in balancing the performance between LTE and WLAN. In the conventional scenario where WLANs are located indoor and LTE eNBs are located outdoor, a plain coexistence without additional mechanism could be acceptable due to high penetration loss of outdoor walls.

Next-generation wireless communications systems are expected to exploit frequency bands above 6 GHz. An important transition towards such bands will be design of channel models capable of supporting the design of efficient air-interface and networks. In this paper, we describe a geometry-based statistical channel model and apply ray-tracing simulation for its validation. Focusing on path loss and root-mean-square (RMS) delay spread as metrics, we show that the proposed modeling approach is flexible and realistic.